US11197669B2 - Device and method for assisting selection of surgical staple height - Google Patents

Abstract

A surgical instrument for assessing a mechanical property of tissue under compression is disclosed herein comprising a handle; an elongated shaft distally disposed to the handle; an end effector distally disposed to the elongated shaft and comprising a first and a second jaw member pivotally engaged with each other to open and close when operated by the handle; a force gauge assembly comprising a compression head and a force transducer; an adjustable spacer assembly disposed on the first jaw member proximally to the force gauge assembly and comprising an adjustable spacer member and a spacer base; a control mechanism supported by the elongated shaft and disposed adjacent to the handle for producing an actuation force for controlling the adjustable spacer assembly; and at least one control link operably coupled with the control mechanism and the spacer base, and configured to transmit the actuation force.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of and priority to U.S. Provisional Patent Applications No. 62/912,659, filed on Oct. 9, 2019 and No. 62/971,161, filed on Feb. 6, 2020, the entire contents of which are incorporated by reference herein.

The present application is related to U.S. patent application Ser. No. 16/932,873, filed on Jul. 20, 2020, U.S. patent application Ser. No. 16/932,876, filed on Jul. 20, 2020 and U.S. patent application Ser. No. 16/852,464, filed on Apr. 18, 2020, which is a Continuation application of U.S. patent application Ser. No. 15/893,638, filed on Feb. 11, 2018, now U.S. Pat. No. 10,682,139, issued on Jun. 16, 2020, the entire contents of which are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a medical device and method for use in surgical procedures. More particularly, the present invention relates to a surgical device and method for assisting selection of surgical staple height in a surgical stapling operation.

BACKGROUND OF THE INVENTION

The utilization of mechanical tissue fastening instruments, notably, open and endoscopic surgical staplers have been increasing steadily in recent years as a substitute for suturing in joining a tissue, joining and cutting a tissue simultaneously and performing anastomosis of tubular organs belonging to the digestive system in a number of surgical disciplines. Over the years these instruments have proven to provide significant clinical benefits of improved patient outcome in addition to procedural benefits of reduced procedure time and simplified surgical tasks when compared to laborious and time consuming suturing, and related cost savings. In certain types of surgical procedures use of surgical staplers has become the preferred method of joining a tissue including the bariatric, thoracic and colorectal surgeries.

There are several known types of surgical stapler instruments specifically adapted for use in various procedures such as end-to-end anastomosis, gastrointestinal anastomosis, endoscopic gastrointestinal anastomosis, and transverse anastomosis. Examples of stapler instruments for these various procedures can be found in U.S. Pat. Nos. 5,915,616; 6,202,914; 5,865,361; and 5,964,394, which are each herein incorporated by reference.

Known endoscopic surgical stapler instruments comprise a handle and an end effector that are fixedly attached to either ends of an elongate shaft and operatively engaged with each other. An end effector simultaneously makes a longitudinal incision in tissue and applies lines of staples on opposing sides of the incision. An end effector includes a pair of opposed jaw members that, if the instrument is intended for endoscopic or laparoscopic applications, are capable of passing through a cannula passageway. One of the jaw members, often referred to as a cartridge jaw member, receives a staple cartridge having at least two laterally spaced rows of staples in an elongate cartridge channel or a cartridge bay. The other jaw member, often referred to as an anvil jaw member, defines an anvil having staple-forming pockets aligned with the rows of staples in the staple cartridge. The instrument commonly includes a plurality of reciprocating wedges which, when driven distally, pass through openings in the staple cartridge and engage drivers supporting the staples to effect the firing of the staples toward the anvil.

In surgical stapling operation a physician operator first positions the end effector of a surgical stapler instrument to capture a target tissue between the two jaw members in open position and then operates the handle to close the two jaw members to clamp and compress the target tissue to a nominal thickness defined by the gap distance between the tissue contacting surfaces of the staple cartridge and the anvil prior to the firing of the staples. In the designs of presently available stapler instruments a physician has no means to control the degree or force of target tissue compression but is presented with a set of standardized staple cartridges colored coded according to the formed height(s) of staples contained therein, which correlates with the gap distance between the tissue contacting surfaces of the staple cartridge and anvil. Presently, the standardized set of staple cartridges, typically color coded white, blue, gold, green and black in the ascending order of staple heights contained therein, includes staples with formed heights between 1 mm and 2.3 mm in discrete increment. There are also in the market a set of staple cartridges, each cartridge containing a combination staples of varying heights with its own unique color coding tailored for application on tissue with varying compressed thickness. In compressing the target tissue the two jaw members comprising the end effector of stapler instrument are subject to a distributed reactionary load from the compressed tissue usually resulting in deflection of the two jaw members increasing progressively along the length thereof going from the proximal to distal end and more so, in the anvil than in the cartridge jaw member which is more substantial and structurally rigid. The corresponding variation in the gap distance between the tissue contacting surfaces of the staple cartridge and the anvil makes the tissue compression non-uniform decreasing progressively going from the proximal to distal ends of the end effector.

The level of tissue compression is one of the key factors that determine success of a surgical stapling operation often defined by adequate hemostasis and minimal damage of tissue along the staple line, and leak-free sealing of the target tubular organ among other considerations. It is known that a desirable clinical outcome of a surgical stapling operation is most likely achieved when the target tissue is compressed to a compression force between 6 g/mm²or 8 g/mm². Since present surgical stapler technology does not provide means to control the compression force of the target tissue a physician needs to choose a staple cartridge out of a standard set that would best approximate the optimal compression force for the target tissue when the two jaw members are closed with the chosen staple cartridge mounted in the cartridge bay. Having no practical means to help direct selection of staple cartridge, for example, accessory tools to directly assess a key mechanical property or condition of the target tissue, a physician is left to rely solely on his or her experience, or educated guess in selecting a staple cartridge, which leaves open possibility of under- or over-compression of the target tissue. Under-compression of tissue could lead to inadequate hemostasis and potential leakage of content contained within the tissue while over-compression to tearing of tissue or ischemia requiring prolonged period of healing. The staple cartridge selection is particularly difficult for a target tissue belonging to an organ with naturally occurring, large thickness variation such as in the stomach or an organ with unknown variation in mechanical properties such as in the lung at different disease state.

Manufacturers of present surgical stapler instruments instruct a physician to verify the adequacy of selected staple cartridge in compressing a target tissue by the feedback force felt in the hand operating the handle of the stapler instrument to apply the tissue compression. The instructions basically say to switch to a new staple cartridge with staples of larger formed height if it is overly difficult to operate the handle to apply compression to the target tissue specifically to guard against over-compression. This method is proven to be hardly practical in the field because the feedback force felt in the palm of the physician's hand may not necessarily correlates with the level of tissue compression due to the facts that the feedback force may be distorted being passed down through mechanical linkages and joints comprising the operating mechanism for the end effector and that the two jaw members comprising the end effector undergoes deflection caused by the reactionary load from the compressed tissue. In addition a unit of change in the compressed tissue thickness represented by the standard set of staple cartridges typically corresponds to only around few tens of gram of force in tissue compression which is barely discernible by the haptic sense felt in the palm of the hand alone even under the best of circumstances. Corresponding instruction for staple cartridge selection for preventing under-compression of a target tissue does not even exist.

U.S. Pat. No. 8,893,946 to Boudreaux et al., which is herein incorporated by reference, describes a surgical instrument that includes components for measuring the thickness of a tissue clamped between the two jaw members of an end effector thereof relying on a strain gauge or strain gauges as a means to generate a signal or signals corresponding to the tissue thickness and/or a compression load applied to the tissue. This disclosure describes the strain gauges as being used stand-alone but fails to describe how the strain gauges are practically implemented, for example, in the form of a load cell, well known to those of skill in the art, to generate such signals that could be converted to the thickness of tissue or the compression load acting thereon. The surgical instrument in this disclosure does not include any means to prevent or compensate for the potential deflection of a jaw member comprising an end effector as a result of a reactionary load from the compressed tissue nor for the effect of the play present in the closure mechanism of the two jaw members comprising the end effector on the tissue thickness measurement. This disclosure also fails to define the thickness of the clamped tissue in such sufficient detail for it to be of practical use in the selection of a staple cartridge for a stapling operation on the tissue.

Therefore, significant needs exist for a surgical device and method that would aid a physician in selecting a staple cartridge from the standard set of staple cartridges.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed toward a surgical device and method for use in surgical procedures. More particularly, the present invention relates to a surgical device and method for assisting selection of a staple cartridge from the standard set of staple cartridges optimal for a target tissue of a surgical stapling operation.

To address the foregoing needs and with other objects in view there are provided, in accordance with the present invention, a surgical device for enabling a surgical stapler instrument to compress a tissue consistently to a predetermined thickness and measure a reactionary load therefrom and a method for assisting a physician in selecting a staple cartridge optimal for a tissue of a surgical stapling operation.

Ina preferred embodiment of the present invention, a compression gauge cartridge for use mounted in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member having a tissue contacting surface, of a surgical stapler instrument to compress a tissue consistently to a predetermined thickness and measure a reactionary load therefrom for assisting selection of a staple cartridge and assessing the condition of the tissue comprises: a cartridge body having a proximal end and a distal end, and a tissue supporting surface, wherein said cartridge body is configured for said compression gauge cartridge to be releasably mounted in said cartridge bay and for said tissue supporting surface to be at least at a predetermined distance from said tissue contacting surface of said anvil jaw member when said cartridge jaw member and said anvil jaw member are in a fully closed position; a force gauge assembly comprising a force transducer and a compression head having a tissue compression face, wherein said force gauge assembly is supported by said cartridge body positioned between said proximal end and said distal end thereof and wherein said compression head is configured and disposed so that said tissue compression face thereof lies substantially closer to said tissue contacting surface of said anvil jaw member than said tissue supporting surface of said cartridge body; and a spacer member extending from said tissue supporting surface of said cartridge body, wherein said compression head comprising said force gauge assembly is positioned distally with respect to said spacer member. In an alternate embodiment said tissue supporting surface of said cartridge body may be contoured in such a way to further reduce compression of said tissue disposed between said tissue supporting surface and said tissue contacting surface when said cartridge jaw member and said anvil jaw member are in a fully closed position.

In an alternate embodiment of the present invention, a compression gauge cartridge for use mounted in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member having a tissue contacting surface, of a surgical stapler instrument to compress a tissue so that said cartridge jaw member and said anvil jaw member come to a predetermined angular positional relationship with each other and measure a reactionary load therefrom for assisting selection of a staple cartridge comprises: a cartridge body having a proximal end and a distal end, and a tissue supporting surface, wherein said cartridge body is configured for said compression gauge cartridge to be releasably mounted in said cartridge bay and for said tissue supporting surface to be at least at a predetermined distance from said tissue contacting surface of said anvil jaw member when said cartridge jaw member and said anvil jaw member are in a fully closed position; and a force gauge assembly comprising a force transducer and a compression head having a tissue compression face, wherein said force gauge assembly is supported by said cartridge body positioned between said proximal end and said distal end thereof and wherein said compression head is configured and disposed so that said tissue compression face thereof lies substantially closer to said tissue contacting surface of said anvil jaw member than said tissue supporting surface of said cartridge body. In an alternate embodiment said tissue supporting surface of said cartridge body may be contoured in such a way to further reduce compression of said tissue disposed between said tissue supporting surface and said tissue contacting surface when said cartridge jaw member and said anvil jaw member are in a fully closed position.

In an embodiment of the present invention, a surgical stapler instrument may further include a spacer block of a predetermined height disposed at a handle comprising said surgical stapler instrument for defining a predetermined extent said handle may be operated to close a cartridge jaw member and an anvil jaw member comprising an end effector comprising said surgical stapler instrument so that said cartridge jaw member and said anvil jaw member come to a predetermined angular positional relationship with each other.

In a preferred embodiment of the present invention, a surgical compression gauge instrument for compressing a tissue consistently to a predetermined thickness and measuring a reactionary load therefrom for assisting selection of a staple cartridge and assessing the condition of the tissue comprises: a handle portion; a body portion extending distally from said handle portion and defining a longitudinal axis; and a tool assembly disposed at a distal end of and operatively connected to said body portion, and comprising a compression gauge jaw member having a proximal end and a distal end and a tissue supporting surface, and an anvil jaw member having a tissue contacting surface, wherein said compression gauge jaw member is configured for said tissue supporting surface thereof to be at least at a predetermined distance from said tissue contacting surface of said anvil jaw member when said compression gauge jaw member and said anvil jaw member are in a fully closed position, and configured to open and close when operated by said handle portion, wherein said compression gauge jaw member comprises a force gauge assembly, supported therein and positioned between said proximal end and said distal end thereof, comprising a force transducer and a compression head having a tissue compression face, wherein said compression head is configured and disposed so that said tissue compression face thereof lies substantially closer to said tissue contacting surface of said anvil jaw member than said tissue supporting surface of said compression gauge jaw member; and a spacer member extending from said tissue supporting surface of said compression gauge jaw member, wherein said compression head comprising said force gauge assembly is positioned distally with respect to said spacer member.

In a preferred embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance, corresponding to a height of staples contained in a predetermined cartridge from the set of standard staple cartridges, between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; comparing said reactionary load reading with a value known to be optimal for a stapling operation of said tissue to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said optimal value and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from the standard set of staple cartridges containing staples of a height corresponding to said predetermined thickness of said compressed tissue if the result of comparison is case (1), or a staple cartridge containing staples of a height smaller than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of a height larger than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In an alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined average height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance, corresponding to an average height of staples contained in a predetermined cartridge from the set of standard staple cartridges, between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; comparing said reactionary load reading with a value known to be optimal for a stapling operation of said tissue to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said optimal value and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from said standard set of staple cartridges containing staples of an average height corresponding to said predetermined thickness of said compressed tissue if the result of comparison is case (1), or a staple cartridge containing staples of an average height smaller than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of an average height larger than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined average height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In another alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance, corresponding to a height of staples contained in a green cartridge from the set of standard staple cartridges, between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; comparing said reactionary load reading with a value known to be optimal for a stapling operation of said tissue to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said optimal value; selecting a green cartridge from the standard set of staple cartridges if the result of comparison is case (1) or a blue cartridge if the result of comparison is case (2), or a black cartridge if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In an alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; providing a reference tissue for which an optimal staple height for a surgical stapling operation is known; comparing said reactionary load reading with a reactionary load from said reference tissue compressed to said predetermined thickness over the same area of said reference tissue as that of said tissue compression face of said compression head to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said reactionary load from said reference tissue and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from the standard set of staple cartridges containing staples of a height known to be optimal for said reference tissue if the result of comparison is case (1), or a staple cartridge containing staples of a height smaller than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of a height larger than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In an alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member having a tissue contacting surface, of a surgical stapler instrument; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured there-between so that said cartridge jaw member and said anvil jaw member come to a predetermined angular positional relationship with each other; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; providing a reference tissue for which an optimal staple height for a surgical stapling operation is known; comparing said reactionary load reading with a reactionary load from said reference tissue compressed so that said cartridge jaw member and said anvil jaw member come to said predetermined angular positional relationship with each other to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said reactionary load from said reference tissue and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from the standard set of staple cartridges containing staples of a height known to be optimal for said reference tissue if the result of comparison is case (1), or a staple cartridge containing staples of a height smaller than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of a height larger than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In order to make an informed selection of a staple cartridge for a tissue of a surgical stapling operation or to assess a condition of a tissue in a surgery, a physician mounts a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member of a surgical stapler instrument prepared to be used for the stapling operation or employ a dedicated surgical instrument with a tool assembly, a jaw member of which is instrumented with a compression gauge device including a force gauge assembly and a spacer member. The physician then operates the handle portion of the surgical stapler instrument or the dedicated surgical instrument to capture a tissue between the two jaw members comprising the end effector or a tool assembly and close the two jaw members to compress the tissue to a predetermined thickness set by the spacer member comprising the compression gauge cartridge or the compression gauge device. The surgical stapler instrument instrumented with the compression gauge cartridge and the dedicated surgical instrument instrumented with the compression gauge device is capable of providing a predetermined gap distance consistently and with a high degree of repeatability between the tissue compression face of the compression head comprising the force gauge assembly and the tissue contacting surface of the anvil jaw member. The compression of tissue takes place over the area covered by the tissue compression face of the compression head, which reduces the tissue to a predetermined thickness corresponding to the predetermined gap distance. Preferably, the predetermined thickness of the compressed tissue is the formed height of staples contained in a green staple cartridge from the standard set of staple cartridges. The compression head transfer a reactionary load from the compressed tissue exerted thereon to the force transducer comprising the force gauge assembly, which is displayed on a force transducer indicator connected to the force transducer comprising the force gauge assembly. Comparing the reactionary load with a known optimal tissue compression force for a surgical stapling operation the physician may decide to choose a green staple cartridge or other staple cartridges, blue or black, containing staples of a height smaller or larger than the green cartridge in the standard set of staple cartridges. Preferably, the control program for the force transducer indicator includes a software function for performing the comparison of the measured reactionary load with a set of values stored in the internal memory to provide a signal indicating a recommendation on the staple cartridge selection, for example, in the form of a color coded signal lights or other easily recognizable forms.

The presently disclosed compression gauge cartridge and method, together with attendant advantages, will be more clearly illustrated below by the description of the drawings and the detailed description of the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The following exemplary figures are provided to supplement the description below and more clearly describe the invention. In the figures, like elements are generally designated with the same reference numeral for illustrative convenience and should not be used to limit the scope of the present invention.

FIG. 1 is a plot of a stress-strain curve of a stomach tissue according to an embodiment of the present invention.

FIG. 2A is a perspective view of an exemplary surgical stapler instrument according to an embodiment of the present invention.

FIG. 2B is a perspective view of an end effector of an exemplary surgical stapler instrument according to an embodiment of the present invention.

FIG. 3A is a perspective view of a compression gauge cartridge disposed in a cartridge bay of a cartridge jaw member of an end effector of an exemplary surgical stapler instrument according to an embodiment of the present invention.

FIG. 3B is a perspective view of a compression gauge cartridge positioned spaced apart from a cartridge bay according to an embodiment of the present invention.

FIG. 3C is an exploded view of a compression gauge cartridge according to an embodiment of the present invention.

FIG. 3D is a perspective view of a compression gauge cartridge with a cartridge body sectioned along theline3D-3D shown inFIG. 3C and spaced apart according to an embodiment of the present invention.

FIG. 4A is a perspective view of a compression gauge cartridge according to an alternate embodiment of the present invention.

FIG. 4B is a perspective view of a compression gauge cartridge, shown inFIG. 4A, with a cartridge body sectioned similarly to that shown inFIG. 3C and spaced apart according to an alternate embodiment of the present invention.

FIG. 5A is a perspective view of a compression gauge cartridge according to another alternate embodiment of the present invention.

FIG. 5B is a perspective view of a compression gauge cartridge, shown inFIG. 5A, with a cartridge body sectioned similarly to that shown inFIG. 3C and spaced apart according to another alternate embodiment of the present invention.

FIG. 6A is a schematic, side elevation view of a tissue captured between an anvil jaw member and a staple cartridge comprising a cartridge jaw member in an open position according to an embodiment of the present invention.

FIG. 6B is a schematic, side elevation view of a tissue compressed between an anvil jaw member and a staple cartridge in a closed position according to an embodiment of the present invention.

FIG. 6C is a perspective view of a cartridge body comprising a compression gauge cartridge according to an embodiment of the present invention.

FIG. 6D is a schematic, side elevation view of a tissue compressed between a compression gauge cartridge comprising a cartridge jaw member and an anvil jaw member in a closed position according to an embodiment of the present invention.

FIG. 6E is a perspective view of a cartridge body comprising a compression gauge cartridge according to an alternate embodiment of the present invention.

FIG. 7A is a perspective view of a force gauge assembly with a compression head set spaced apart according to an embodiment of the present invention.

FIG. 7B is a perspective view of a compression head comprising a force gauge assembly sectioned along a long symmetry plane and spaced apart according to an alternate embodiment of the present invention.

FIG. 7C is a perspective view of a signal conduction means and a cartridge jaw member partially broken away according to an embodiment of the present invention.

FIG. 7D is a perspective view of a signal conduction means comprising a compression gauge cartridge partially broken away according to an alternate embodiment of the present invention.

FIG. 8A is a perspective view of a force gauge assembly with a compression head set spaced apart therefrom according to an alternate embodiment of the present invention.

FIG. 8B is a perspective view of a compression head comprising a force gauge assembly sectioned along a long symmetry plane and spaced apart according to an another alternate embodiment of the present invention.

FIG. 8C is a perspective view of a cantilevered compression head comprising a force gauge assembly disposed in a cartridge body shown partially broken away, sectioned along a symmetry plane and spaced apart according to an another alternate embodiment of the present invention.

FIG. 8D is a perspective view of a deformable compression head comprising a force gauge assembly disposed in a cartridge body shown partially broken away, sectioned along a symmetry plane and spaced apart according to an another alternate embodiment of the present invention.

FIG. 9A is a perspective view of a force gauge assembly with a compression head set spaced apart therefrom according to another alternate embodiment of the present invention.

FIG. 9B is a perspective view of a compression head comprising a force gauge assembly sectioned along a symmetry plane and spaced apart according to an another alternate embodiment of the present invention.

FIGS. 10A and 10B are side elevation views of a compression gauge cartridge comprising a cartridge jaw member and an anvil jaw member according to embodiments of the present invention.

FIG. 11A is a perspective view of a cartridge body and a repositionable spacer member comprising a compression gauge cartridge according to an embodiment of the present invention.

FIGS. 11B and 11C are perspective views of a spacer member with an extension member according to embodiments of the present invention.

FIG. 11D is a perspective view of a protective cover disposed on a cartridge body comprising a compression gauge cartridge according to an embodiment of the present invention.

FIGS. 12A-12C are perspective views of a cartridge body and a cartridge bay, partially broken away and sectioned and spaced apart, and an adjustable spacer member comprising a compression gauge cartridge according to various embodiments of the present invention.

FIGS. 12D and 12E are perspective views of a cartridge body and a cartridge bay, partially broken away and sectioned and spaced apart, and a rotatable spacer member comprising a compression gauge cartridge according to an alternate embodiment of the present invention.

FIG. 13A is a schematic, side elevation view of a reference block, a compression gauge cartridge and an anvil jaw member according to an embodiment of the present invention.

FIG. 13B is a perspective view of a protective cover disposed on a cartridge body according to an embodiment of the present invention.

FIG. 13C is a perspective view of a cartridge body, a protective cover and a cartridge bay, partially broken away and sectioned and spaced apart, and an adjustable spacer member biased by a spring according to an embodiment of the present invention.

FIG. 14 is an assembly view of a compression gauge cartridge comprising two parts according to an alternate embodiment of the present invention.

FIG. 15 is a perspective view of a surgical compression gauge instrument comprising a compression gauge jaw member according to an embodiment of the present invention.

FIG. 16 is a perspective view of a compression gauge cartridge according to an alternate embodiment of the present invention.

FIG. 17 is a side elevation view of a compression gauge cartridge comprising a cartridge jaw member and an anvil jaw member according to embodiments of the present invention.

FIG. 18 is a perspective view of a surgical stapler instrument according to an embodiment of the present invention.

FIG. 19 is a perspective view of a compression gauge cartridge according to an alternate embodiment of the present invention.

FIG. 20 is a perspective view of a compression gauge cartridge with a cartridge body sectioned similarly to that shown inFIG. 3C and spaced apart according to an alternate embodiment of the present invention.

FIG. 21 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a spacer assembly according to an embodiment of the present invention.

FIG. 22A is a perspective view of a spacer assembly with the stopper in the path of the spacer member according to an embodiment of the present invention.

FIG. 22B is a perspective view of a spacer assembly with the stopper out of the path of the spacer member according to an embodiment of the present invention.

FIG. 23A is a perspective view of a stopper comprising a plurality of steps joined with a stopper control link according to an embodiment of the present invention.

FIG. 23B is a perspective view of a spacer member held in position resting at a step of a stopper comprising a plurality of steps joined with a stopper control link according to an embodiment of the present invention.

FIG. 23C is a perspective view of a spacer member with a stopper, comprising a plurality of steps joined with a stopper control link, out of the path thereof according to an embodiment of the present invention.

FIG. 24 is a perspective view of a stopper comprising a sloped face joined with a stopper control link according to an embodiment of the present invention.

FIG. 25 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a spacer assembly according to an embodiment of the present invention.

FIG. 26A is a perspective view of a spacer assembly with the stopper in the path of the spacer member according to an embodiment of the present invention.

FIG. 26B is a perspective view of a spacer assembly with the stopper out of the path of the spacer member according to an embodiment of the present invention.

FIG. 27 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a plurality of spacer assemblies according to an embodiment of the present invention.

FIGS. 28A-28C are perspective views of a plurality of spacer assemblies according to an embodiment of the present invention.

FIG. 29 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a spacer assembly according to an embodiment of the present invention.

FIG. 30 is an exploded view of a spacer assembly according to an embodiment of the present invention.

FIGS. 31A-31C are perspective views of a spacer assembly according to an embodiment of the present invention.

FIG. 32 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a gap sensor according to an embodiment of the present invention.

FIG. 33 is an exploded view of a gap sensor according to an embodiment of the present invention.

FIG. 34 is a perspective view of a piston comprising a gap sensor sectioned apart according to an embodiment of the present invention.

FIG. 35 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a gap sensor according to an embodiment of the present invention.

FIG. 36 is a perspective view of a gap sensor according to an embodiment of the present invention.

FIG. 37 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a gap sensor according to an embodiment of the present invention.

FIG. 38 is a perspective view of a gap sensor according to an embodiment of the present invention.

FIG. 39 is a perspective view of a cartridge body, partially broken away, and sectioned and spaced apart, and a gap sensor according to an embodiment of the present invention.

FIG. 40 is an exploded view of a gap sensor according to an embodiment of the present invention.

FIGS. 41-44 is a side elevation view of a compression gauge cartridge and an anvil jaw member comprising an end effector of a surgical stapler instrument instrumented with the compression gauge cartridge according to an embodiment of the present invention.

FIGS. 45A and 45B is a perspective view of a cartridge body partially broken away and partially broken away, sectioned and spaced apart, respectively, and a gap sensor according to an embodiment of the present invention.

FIG. 46 is a perspective view of a gap sensor according to an embodiment of the present invention.

FIG. 47 is a perspective view of a surgical instrument according to an embodiment of the present invention.

FIG. 48 is a perspective view of a surgical instrument, shown inFIG. 47, partially sectioned apart according to an embodiment of the present invention.

FIG. 49 is a perspective view of a part of a surgical instrument, shown inFIG. 47, partially sectioned apart according to an embodiment of the present invention.

FIG. 50 is a perspective view of a part of a surgical instrument, shown inFIG. 47, partially sectioned apart according to an embodiment of the present invention.

FIG. 51 is a perspective view of a part of a surgical instrument, shown inFIG. 47, partially sectioned apart according to an embodiment of the present invention.

FIG. 52 is a perspective view of a surgical instrument according to another embodiment of the present invention.

FIG. 53 is a perspective view of a surgical instrument, shown inFIG. 52, partially sectioned apart according to an embodiment of the present invention.

FIG. 54 is a perspective view of a compression gauge jaw member broken away and partially sectioned apart according to an embodiment of the present invention.

FIG. 55 is an exploded view of a spacer assembly according to an embodiment of the present invention.

FIG. 56 is an exploded view of a spacer assembly according to another embodiment of the present invention.

FIG. 57 is a perspective view of a spacer base control link according to an embodiment of the present invention.

FIG. 58 is a perspective view of a spacer base control link according to another embodiment of the present invention.

FIG. 59 is a perspective view of a spacer base control mechanism according to an embodiment of the present invention.

FIG. 60 is a perspective view of a spacer base control mechanism according to another embodiment of the present invention.

FIG. 61 is a perspective view of a spacer base control mechanism according to another embodiment of the present invention.

FIG. 62 is a perspective view of a spacer base control mechanism according to another embodiment of the present invention.

FIG. 63 is a perspective view of a spacer base control mechanism according to another embodiment of the present invention.

FIG. 64 is a perspective view of a spacer base control mechanism according to another embodiment of the present invention.

FIG. 65 is a perspective view of a power driven surgical instrument according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The novel features of the present invention will become apparent to those of skill in the art upon examination of the following detailed description of the invention. It should be understood, however, that the detailed description of the invention and the specific examples presented, while indicating certain embodiments of the present invention, are provided for illustration purposes only because various changes and modifications within the spirit and scope of the invention will become apparent to those of skill in the art from the detailed description of the invention and claims that follow.

Embodiments of the presently disclosed surgical device will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. In the drawings and in the description which follows, the term “proximal”, as is traditional, will refer to the end of the surgical device which is closest to a physician while the term “distal” will refer to the end of the device which is furthest from a physician. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and absolute. The terms “force”, “load”, and “force load” may be used interchangeably herein to describe various mechanical forces including a reaction thereto. It should be appreciated that spatial terms such as vertical, horizontal, right, left or above, etc., are given herein with reference to the figures. In actual practice, however, a surgical device or instrument may be oriented at various angles and, as such, these spatial terms are used relative to the surgical device or instrument.

The present invention relates to a surgical device and method for use in a surgical procedure. More particularly, the present invention relates to a surgical device for enabling compression of a tissue consistently to a predetermined thickness with a high degree of repeatability and measurement of a reactionary load from the compressed tissue to assist in the selection of a staple cartridge from the standard set of staple cartridges optimal for the tissue of a surgical stapling operation and to assess a condition of a tissue of a surgical operation in a surgical procedure. In an embodiment a surgical device of the present invention may be advantageously adapted for use, as an add-on accessory, mounted in a cartridge bay comprising a cartridge jaw member of an end effector of an endoscopic surgical stapler instrument. A surgical device of the present invention may be configured to include retention features similar to a staple cartridge for releasably mounting in an open cartridge bay, if available in a surgical stapler instrument, or otherwise fixedly integrated with a cartridge jaw member of a disposable reload unit found in certain surgical stapler instruments in the market. Advantages of a surgical device of the present invention implemented as an add-on accessory to existing surgical stapler instrument include a reduced cost of use and ease of use to a physician who is already familiar with the operation of such surgical stapler instrument. In an alternate embodiment a surgical device of the present invention may be integrated with or configured as an add-on accessory to a surgical instrument dedicated to implementation of the capabilities offered by a surgical device of the present invention, which may generally comprise two opposing jaw members comprising a tool assembly, corresponding to an end effector of a surgical stapler instrument, fixedly and operably attached to a handle assembly via an elongate body and configured to open and close when operated by the handle assembly. Although the implementation and operation of a surgical device in various embodiments of the present invention will be described in the following as it relates to a endoscopic surgical stapler instrument and endoscopic surgical instrument, it should be apparent to those of skill in the art that the aspects of the present disclosure may be readily adapted for use with other surgical stapler instruments as well as other types of surgical instruments.

The present invention is being discussed in terms of endoscopic procedures and apparatus. However, use herein of terms such as “endoscopic”, should not be construed to limit the present invention to a surgical instrument for use only in conjunction with an endoscopic tube (i.e., trocar). On the contrary, it is to be understood that the present invention may find use in any procedure where access is limited to a small incision, including but not limited to laparoscopic procedures, as well as open procedures.

The characteristic behavior of a tissue undergoing deformation under external stress load, for example, a compressive stress load applied by a pair of jaw members comprising an end effector of a surgical stapler instrument, has been widely studied (for example, Jacob Rosen et. al., “Biomechanical Properties of Abdominal Organs In Vivo and Postmortem Under Compression Loads,” Journal of Biomedical Engineering, Vol. 130, pp. 1-17) and is generally represented by a stress-strain curve plot, well known to those of skill in the art, shown inFIG. 1 in an exemplary representation for a stomach tissue. In response to a compressive stress load, depicted in the vertical axis of the plot, the stomach tissue undergoes a rapid deformation, represented as strain, defined as a percentile reduction in tissue thickness, and depicted in the horizontal axis of the plot, in response to a relatively small change in the compressive stress load at the lower level thereof. At the higher level the stress-strain curve becomes close to a line indicating a linear elastic behavior of the stomach tissue characterized by an elastic modulus defined as the largely constant slope of the stress-strain curve. This general characteristic behavior of a stomach tissue as well as other bodily tissue under a compressive stress load is often described as a viscoelastic behavior, by those of skill in the art, exhibiting typical characteristics of both a viscous liquid and an elastic solid subject to an external compressive stress load. The initial rapid deformation of the stomach tissue at the lower level of compressive stress load is largely due to initial displacement of viscous, liquid-like components of the tissue causing a rapid reduction in thickness of the tissue under a relatively weak compressive stress load applied to an area thereof. The elastic response of the tissue at the higher level of compressive stress load is largely due to relatively immobile fibrous, solid-like components of the tissue responding to the compressive stress load collectively with substantially elastic behavior. At further higher up in the compressive stress load level the strain of the tissue reaches what is known to those of skill in the art as the ultimate tensile strength or the breaking point, labeled with a letter C inFIG. 1 where the internal structure of the tissue starts to break down and eventually completely loses ability to recoverably respond to an additional compressive stress load.

The almost linear correlation between the stress and strain of a stomach tissue and, to an extent, similar behavior exhibited in other bodily tissues at the compressive stress load interval of interest, particularly, as it relates to a surgical stapling operation, indicated by a bracket labeled with a letter S inFIG. 1, makes it possible to infer the change in the compressive stress load acting on the stomach tissue if the change in the thickness of the stomach tissue resulting therefrom is known and vice versa. Based on this observation, one could devise a practical scheme for the selection of a staple cartridge, containing staples of optimal height for a tissue of a surgical stapling operation, from the standard set of staple cartridges, which generally include steps of compressing a tissue to a predetermined thickness, i.e., to a predetermined strain; measuring a compressive stress load, i.e., a reactionary load from the compressed tissue, required to cause such reduction in thickness; comparing the measured compressive stress load to the known optimal value for a surgical stapling operation, for example, 8 g/mm²as previously described in the BACKGROUND, noting the size of difference between the measured compressive stress load and the optimal value; and based on the result of comparison, deciding whether to select a staple cartridge with staples of formed height closest to the compressed tissue thickness or of different formed heights taking into account the size of difference, i.e., change the strain induced on the tissue to a direction and level to modify the compressive stress load exerted on the tissue to be closer to the optimal value. As will be described in detail hereinafter, implementation of such a scheme on a platform of existing surgical instrument, particularly, a surgical stapler instrument may heavily rely on being able to methodically constrain the closure of the two jaw members comprising an end effector or a tool assembly to compress a tissue consistently to a predetermined thickness with a high degree of repeatability and to measure a reactionary load from the compressed tissue.

Referring toFIGS. 2A and 2B, an exemplarysurgical stapler instrument10 and an enlarged view of anend effector20 thereof are shown.Surgical stapling instrument10 includes ahandle assembly11,end effector20 and anelongate tube12 that operatively connectshandle assembly11 andend effector20 through a drive mechanism (not shown in the FIGURES).End effector20 comprises afirst jaw member21 and asecond jaw member22.Second jaw member22 comprises anelongate channel23, sometimes referred to as a cartridge bay, configured to receive astaple cartridge25 having atissue contacting surface26.First jaw member21 comprises an anvil having atissue contacting surface24 that is aligned and pivotally engaged through a pivot mechanism (not shown) withsecond jaw member22 forming a pair of opposed jaw members that open and close, when driven by the drive mechanism operated withhandle assembly11 by a physician, to capture and compress a tissue there-between for stapling. Various different drive mechanisms, well known to those of skill in the art, are employed to actuate a pivot mechanism joining twojaw members21,22 to cause opening and closing thereof including a drive pin and cam groove mechanism, reciprocating closure tube assemblies, gear mechanisms, rack and pinion mechanism, and pulley mechanism, etc. Typically, handleassembly11 drivingend effector20 is configured in such a way that first andsecond jaw members21,22 are capable of rigidly holding their approximated positional relationship, i.e., a locked position, when closed to capture and compress the tissue prior to the deployment and formation of staples. Those of skill in the art would appreciate that the exemplary surgical stapler instrument depicted in the FIGURES comprises one surgical stapler instrument version with which various embodiments of a surgical device of the present invention may be advantageously employed.

The pivotal engagement between twojaw members21,22 comprising anend effector20 may take various configurations including a hinge about which twojaw members21,22 are configured to rotate and a cam groove along which a drive pin is configured to translate to open orclose end effector20. The clearances built in the mechanical designs of the pivot mechanism and the drive mechanism to ensure smooth operations thereof and, to a lesser extent, unavoidable manufacturing tolerances in the parts thereof inevitably introduce a measurable play in the pivotal motion of twojaw members21,22, which manifests as an inherent uncertainty in the positional relationship between twojaw members21,22, particularly, in the relative angular position thereof even under unloaded condition, that is, without a tissue captured and compressed there-between. Of particular significance to a device and method in an embodiment of the present invention is a variation in the relative angular position of the two jaw members that may be appropriately referred as a backlash, i.e., a tendency for the closed jaw members to open back up, the size of which is strongly dependent on the level of compression of a tissue there-between. The variation in the backlash introduces, in effect, variability in the gap distance, defined as a distance betweentissue contacting surfaces24,26, of twojaw members21,22 at a given position along the length ofend effector20, which also varies with the size of a reactionary load from the compressed tissue. The uncertainty in the gap distance due to the play in the pivot mechanism tends to become more pronounced going farther away distally from pivot mechanism due to a lever arm effect. A reactionary load from the compressed tissue acting on twojaw members21,22 may add to variability in the gap distance by potentially causing a deformation or a deflection of twojaw members21,22, more likely, an anvil the less stiffer of the two, the degree of which differs depending the size of the reactionary load and, therefore, is not easy to estimate or measure. In practice, the gap distance has been observed to vary very significantly from one tissue to another mostly due to the deflection of the anvil, irrespective of particular brands of surgical stapler instrument in the market, and in fact, there are no dedicated mechanisms implemented on the existing surgical stapler instrument products to precisely and actively control the gap distance during compression of a tissue. Instead, when critically needed, for example, in case of a very thick tissue, an external constraining means is employed to control the gap distance to some extent in certain surgical stapler instruments in the market. For this reason, a surgical stapler instrument presently being marketed does not make a suitable platform on which to implement the staple cartridge selection scheme, described previously, which hinges on an ability to compress a tissue consistently to a well defined thickness and measure a reactionary load therefrom. A surgical device and method proposed in this disclosure seeks to remedy such deficiencies in a surgical stapler instrument or a new surgical instrument dedicated for implementation of such a scheme with a mechanical and operational configuration similar to those of a surgical stapler instrument without requiring a radical redesign of the instruments by providing relatively simple features that are added-on to help bring under control the variability in the gap distance between the two jaw members comprising an end effector or a tool assembly and to introduce a capability to the instruments to measure a reactionary load from the compressed tissue as will be described hereinafter.

Referring toFIG. 3A, acompression gauge cartridge30 is shown, in a perspective view, mounted incartridge bay23 ofcartridge jaw member22 ofend effector20 ofsurgical stapler instrument10, as shown inFIGS. 2A and 2B, for compressing a tissue consistently to a predetermined thickness and measuring a reactionary load therefrom in an embodiment of the present invention.Anvil jaw member21 is omitted for clarity inFIG. 3A and a pivot mechanism joining the twojaw members21,22 is schematically represented by a symbol labeled with a letter P and a pivotal motion by a double headed, curved arrow labeled with a letter A. InFIG. 3Bcompression gauge cartridge30 is shown released fromcartridge bay23. Referring toFIG. 3C, details of construction ofcompression gauge cartridge30 is shown in an exploded view in an embodiment of the present invention. In a preferred embodiment of the present invention, compression gauge cartridge30 for use mounted in cartridge bay23 of cartridge jaw member22 comprising end effector20 of surgical stapler instrument10, together with anvil jaw member21 having a tissue contacting surface24, to compress a tissue consistently to a predetermined thickness and measure a reactionary load therefrom for assisting in selection of a staple cartridge optimal for a tissue of a surgical stapling operation and assessing a condition of a tissue of a surgical operation comprises: a cartridge body31 having a proximal end32 and a distal end33, and a tissue supporting surface34 corresponding to tissue contacting surface26 of staple cartridge25, wherein cartridge body31 may be configured for compression gauge cartridge30 to be releasably mounted in cartridge bay23 and for tissue supporting surface34 to be at least at a predetermined distance from tissue contacting surface24 of anvil jaw member21 when cartridge jaw member22 and anvil jaw member21 are in a fully closed position; a force gauge assembly40 comprising a force transducer41 and a compression head45 having a tissue compression face46, wherein force gauge assembly40 may be supported by cartridge body31 positioned between proximal end32 and distal end33 thereof, and wherein compression head45 comprising said force gauge assembly40 may be configured and disposed so that tissue compression face46 thereof may lie substantially closer to tissue contacting surface24 of anvil jaw member21 than tissue supporting surface34 of cartridge body31; and a spacer member50 extending from tissue supporting surface34 of said cartridge body31, wherein force gauge assembly40 may be positioned distally with respect to spacer member50. In an alternate embodimenttissue supporting surface34 ofcartridge body31 may be contoured in such a way to further reduce compression of a tissue disposed betweentissue supporting surface34 andtissue contacting surface21 whencartridge jaw member22 andanvil jaw member21 are in a fully closed position. Further details ofcompression gauge cartridge30 can be seen inFIG. 3D showing, in a perspective view,cartridge body31 sectioned along theline3D-3D shown inFIG. 3C and spaced apart in an embodiment of the present invention. As will become more clear with the following description,compression gauge cartridge30 is configured to allow an existing surgical stapler instrument to be used without modification in applying a compression to a predetermined area of a tissue captured between the two jaw members comprising an end effector thereof consistently and with a high degree of repeatability to a predetermined thickness substantially free of variations of mechanical and structural origins and measuring a reactionary load from the compressed area of the tissue dynamically throughout the compression operation. In an embodiment of the presentinvention cartridge body31 comprisingcompression gauge cartridge30 may be configured forcompression gauge cartridge30 to be releasably mounted and securely retained incartridge bay23 comprisingcartridge jaw member22 ofend effector20. In an alternateembodiment cartridge body31 comprisingcompression gauge cartridge30 may be configured to be fixedly mounted incartridge bay23 to be integrated withcartridge jaw member22 ofend effector20 ofsurgical stapler instrument10. In another alternateembodiment cartridge body31 comprisingcompression gauge cartridge30 may be configured to be fixedly mounted in a cartridge bay to be integrated with a cartridge jaw member of an end effector comprising a disposable reload unit of a certain surgical stapler instrument product in the market.

Referring toFIGS. 3A-3D force transducer41 comprisingforce gauge assembly40 is depicted as having a configuration of a beam supported bycartridge body31 housed in acavity35 therein in an embodiment of the present invention. In an alternateembodiment force transducer41 comprisingforce gauge assembly40 may have a configuration of a button supported bycartridge body31 housed in acavity35 therein as shown inFIGS. 4A and 4B in similar arrangements toFIGS. 3A and 3D, respectively. In another alternateembodiment force transducer41 comprisingforce gauge assembly40 may have a substantially planar configuration supported bycartridge body31 disposed ontissue supporting surface34 thereof as shown inFIGS. 5A and 5B in similar arrangements toFIGS. 3A and 3D, respectively. In various embodiments of the presentinvention cartridge body31 comprisingcompression gauge cartridge30 provides a structurally stable platform upon whichforce transducer41 relies in performing a force measurement operation exerted thereon. More detailed descriptions will follow hereinafter in a section dedicated to the force transducer.

In an embodiment of the presentinvention cartridge body31 comprisingcompression gauge cartridge30 may be configured to include selected design features similar to those found in a conventional staple cartridge that allow a conventional staple cartridge to be releasably mounted and securely retained in a cartridge bay of a cartridge jaw member during a stapling operation. In an alternateembodiment cartridge body31 may include additional design features for releasable mounting and secure retention thereof in a cartridge bay and safety features for safe and effective use of a surgical stapler instrument instrumented withcompression gauge cartridge30 by a physician with average level of experience and skill in use of an ordinary surgical stapler instrument. In an embodiment, materials and method of manufacture substantially similar to those used to construct a conventional staple cartridge may be employed and appropriately adapted to manufacturecartridge body31 comprisingcompression gauge cartridge30. In an alternateembodiment cartridge body31 may include structural reinforcements and/or unconventional construction materials, not ordinarily found in a conventional staple cartridge, to ensure proper operation offorce gauge assembly40 comprisingcompression gauge cartridge30 and compression of a tissue in cooperation with an anvil jaw member comprising an end effector. As will be described hereinafter, the distribution of a reactionary load oncartridge body31 from a tissue under compression in operation ofsurgical stapler instrument10 instrumented withcompression gauge cartridge30 may be different, by design, from that on a conventional staple cartridge mounted in a cartridge bay of the same or comparable surgical stapler instrument in an embodiment of the present invention.

Referring to backFIGS. 3C and 3D, in an embodiment of the presentinvention cartridge body31 may be configured to supportforce gauge assembly40 in anopen cavity35 defined therein with anopening36 disposed ontissue supporting surface34 interconnectingcavity35 and an external space abovetissue supporting surface34, through whichcompression head45 comprisingforce gauge assembly40 is disposed. In anembodiment opening36 may be hermetically capped with aseal member37 to prevent introduction of unwanted contaminant, such as bodily fluid, intocavity35.Seal member37 may be configured to be in contact withtissue compression face46 ofcompression head45 and provided with sufficient flexibility or, otherwise, a freedom of movement to allow displacement ofcompression head45 in response to a load exerted thereto from a compressed tissue to take place substantially freely, which is generally very small and required in a normal operation offorce transducer41, as will be described later in a dedicated section. In an alternateembodiment seal member37 may be integrated withcompression head45 ontissue compression face46 thereof to substantially freely move concurrently therewith. In anembodiment cavity35 may be configured, preferably, to substantially rigidly hold a stationary portion offorce transducer41 of a beam configuration to provide a structural support necessary for optimal operation thereof and to leave sufficient space to ensure unobstructed deflection of a deflectable portion offorce transducer41 and compression head engaged therewith, which is a key aspect of force measurement operation of a force transducer of a beam configuration, as is well known to those of skill in the art. Referring toFIG. 4B, in an embodiment of thepresent invention cavity35 may be configured to accommodate to rigidly holdforce transducer41 of a button configuration and leave sufficient space for free movement ofcompression head45 engaged therewith. In a furtherembodiment cartridge body31 may be configured to supportforce gauge assembly40 of a planar configuration substantially ontissue supporting surface34 as shown inFIGS. 5A and 5B. In an embodiment aretention feature49 may be provided to securely positionforce gauge assembly40 ontissue supporting surface34.

Referring toFIGS. 6A and 6B, schematically showing a tissue T captured and compressed, respectively, betweenanvil jaw member21 and aconventional staple cartridge25 representing acartridge jaw member22 as shown inFIG. 2B, the distributed reactionary load from compressed tissue T over the length ofanvil jaw member21 comprisingend effector20 often causesanvil jaw member21 to deflect to a substantial degree typically being less stiffer thancartridge jaw member22 instrumented withstaple cartridge25. The extent, to whichanvil jaw member21 deflects, strongly depends on the degree of compression of tissue T and gradually increases as one goes distally along the length ofend effector20 from pivot mechanism P due to a cumulative nature of the reactionary load from compressed tissue T. This is a major reason why it is not practically possible to controllably compress a tissue consistently to a known thickness with existing surgical stapler instrument mounted with a conventional stapler cartridge in a cartridge jaw member thereof in addition the inevitable plays in the pivot and drive mechanisms.

With a view to substantially eliminate incontrollable deflection of an anvil jaw member, comprising an end effector together with a cartridge jaw member instrumented with a compression gauge cartridge, in performing tissue compression captured there-between, in an embodiment of the present invention,cartridge body31, as shown inFIG. 6C in a perspective view, may be configured so thattissue supporting surface34 thereof may be at the minimum at a predetermined distance from a tissue contacting surface of an anvil jaw member when a cartridge jaw member and an anvil jaw member are in a fully closed position with or without a tissue captured and compressed there-between. Preferably, the gap distance, defined as a distance betweentissue supporting surface34 and the tissue contacting surface of an anvil jaw member, at a position along the length of the end effector may be substantially larger than the largest gap distance provided by any one from the standard set of staple cartridges at the same position and under the same loading condition from the compressed tissue, if present, so that compression of a tissue disposed over an area covered bytissue supporting surface34 may be minimized to substantially eliminate a distributed reactionary load acting on the anvil jaw member. In an embodimenttissue supporting surface34 may include surface contours such as arecess38 in order to further reduce compression applied to a tissue in contact therewith. The need to keep the tissue compression under control over the area oftissue supporting surface34 must be balanced against the requirement for the structural stiffness of a cartridge jaw member to guard against deformation thereof. Referring back toFIG. 3B, in an embodiment of the presentinvention cartridge body31 may be configured fortissue supporting surface34 thereof to lie substantially even with atop portion28 ofcartridge bay23. In an alternate embodiment,cartridge body31 may be configured fortissue supporting surface34 thereof to lie substantially abovetop portion28. In another alternate embodiment,cartridge body31 may be configured fortissue supporting surface34 thereof to lie substantially belowtop portion28.

Located at a predetermined position along the length ofcartridge body31 ontissue supporting surface34 thereof is anopening36, as shown inFIGS. 3C, 3D and 4B, in an embodiment of the present invention, through whichcompression head45 comprisingforce gauge assembly40 is disposed. In an alternate embodiment, as shown inFIGS. 5A and 5B, forcegauge assembly40 comprisingforce transducer41 of a planar configuration andcompression head45 may be disposed at a predetermined position along the length ofcartridge body31 ontissue supporting surface34. In a preferred embodiment of the presentinvention compression head45 comprisingforce gauge assembly40 may be configured and disposed with respect tocartridge body31 so thattissue compression face46 thereof lie substantially abovetissue supporting surface34 ofcartridge body31 and closer totissue contacting surface24 ofanvil jaw member21, as shown inFIG. 2B, thantissue supporting surface34 ofcartridge body31 whencartridge jaw member22 andanvil jaw member21 are in a fully closed position. Under such configuration, a tissue captured between a compression gauge cartridge mounted in a cartridge bay of a cartridge jaw member and an anvil jaw member experiences compression substantially exclusively over the area covered bytissue compression face46 when two jaw members are in a fully closed position, as schematically illustrated inFIG. 6D in an embodiment, where a predetermined gap distance overtissue compression face46 or a predetermined thickness to which a tissue is compressed is labeled by a letter G. In an embodiment of the present invention the area coveredtissue compression face46 may be varied in order to control a reactionary load from a tissue compressed thereon and substantially eliminate potential deflection of an anvil jaw member resulting therefrom. In an alternate embodiment, the position along the length of the end effector ofcompression head45 comprising force gauge assembly may be varied to control a lever arm effect, as previously described, of a reactionary load from a tissue compressed thereon and substantially eliminate potential deflection of an anvil jaw member resulting therefrom as schematically shown inFIG. 6E. In another alternate embodiment, the area oftissue compression face46 and the position along the length of the end effector ofcompression head45 may be jointly varied.

Referring toFIGS. 3C-4B andFIGS. 7A and 8A showing, in a perspective view, aforce gauge assembly40 comprisingforce transducer41 andcompression head45 wherecompression head45 is shown spaced apart fromforce transducer41, in an embodiment of the present invention, forcegauge assembly40 may be disposed forcompression head45 to be located at a predetermined position along the length ofcartridge body31 betweenproximal end33 anddistal end32 thereof to provide a measurement of a reactionary load from a tissue compressed in a gap between a tissue contacting surface of an anvil jaw member andtissue compression face46 ofcompression head45. In a preferredembodiment force transducer41 may be a strain gauge based load cell of various configurations capable of generating an electrical signal when stimulated including load cells of a beam configuration including, for example, a cantilever bending beam and a parallel bending beam, as schematically illustrated inFIG. 7A, and of a button configuration, as schematically illustrated inFIG. 8A, as are well known to those of skill in the art. Strain gauge based load cells are widely available from a multitude of vendors at relatively low price levels due to their wide spread uses in industrial applications and consumer weight measurement equipments such as personal and kitchen electronic scales. In an embodiment of the present invention there is provided a signal conduction means48 electrically connected to forcetransducer41 for conducting a signal therefrom to a force transducer indicator or a controller (not shown in the FIGURES) disposed remotely from the surgical site, for example, external to a surgery patient. Appropriate signal conduction means48 for a strain gauge based load cell and other types of load cell generating an electric signal includes a flexible flat cable and thin gauge electrical wires, both of which are widely available commercially at low cost and of such a small thickness to be able to freely pass through an annular gap between an elongate tube of a surgical stapler instrument and the inside wall of a trocar through which the instrument is deployed. In an alternateembodiment force transducer41 may be a load cell of a planar configuration, as schematically illustrated inFIG. 9A, a piezoelectric load cell capable of generating an electrical signal when stimulated, commercially available from a multiple vendors, and a resistive film type force sensor capable of generating an electrical signal when stimulated, for example, FlexiForce Sensor® commercially available from Tekscan Inc.

Preferably, signal conduction means48, appropriately selected forforce transducer41, may work bi-directionally conducting a signal fromforce transducer41 to a force transducer indicator or a controller disposed remotely from a surgical site for signal processing and display of result therefrom and providing a power and control signals needed for operation of force transducer. As shown inFIG. 7C, signal conduction means48 may be routed to pass around a distal end ofcartridge jaw member23 as it exitscartridge body31 in an embodiment of the present invention. As shown inFIG. 7D, in an alternate embodiment, signal conduction means48 may be configured to comprise at least two parts, one part connected to forcetransducer41 on one end and terminating with aconnector43 on the other end, and the other part connected to a force transducer indicator on one end and terminating to aconnector42 complementary toconnector43 on the other end. In an embodiment a force transducer indicator or a controller may be disposed externally to the patient and may include an off-the-shelf, commercial weight indicator unit, a custom designed, microprocessor controlled indicator and a signal processor electronics controlled by a computer with a display. In an alternate embodiment of the present invention, at least for a force transducer configured to be electrically powered and generate an electric signal when stimulated, an electrical power source, for example, a battery, and at least a part of processing and display circuitry may be disposed in and supported by a cartridge body comprising a compression gauge cartridge. In another alternate embodiment the cartridge body may further include a wireless communication means for wirelessly sending a signal to an indicator or a controller disposed externally from a surgical site for further processing and display.

In an embodiment,force transducer41 may be dimensionally adaptable for use supported in a cartridge body disposed in a cartridge bay of a cartridge jaw member of an end effector. In an alternate embodiment,force transducer41 may be dimensionally adaptable for use supported in one of the jaw members comprising an end effector of a surgical instrument dedicated to implementation of the present invention. Preferably, the deflection of a deflectable portion offorce transducer41, which normally accompanies operation offorce transducer41 in varying forms and to a different degree, at a maximum level of the reactionary load from the compressed tissue does not exceed a predetermined fraction of a strain induced on the tissue by the compression applied thereto. As previously described in reference toFIG. 1, a relatively small change in the strain of a tissue, for example, due to interaction withforce transducer41, could result in a substantial variation in the stress thereof potentially skewing the measurement of the reactionary load therefrom. Typically, a maximum deflection a strain gauge based load cell or a hydraulic load cell experiences at the load limit does not exceed a few thousandths of an inch easily satisfying the requirement for use on a tissue. A load cell of a planar configuration, at least those include in the examples described previously, does not require any deflection to perform a force measurement.

In an embodiment of the present invention,compression head45 comprisingforce gauge assembly40 mechanically interfaces between a tissue undergoing compression andforce transducer41 for measuring a reactionary force therefrom. Referring toFIGS. 3A-5B and 7A, 8A and 9A, in anembodiment compression head45 may be configured and disposed, with respect tocartridge body31, to contactforce transducer41 on one end, atransducer contact face47, and the tissue on the other end,tissue compression face46 participating in compression of the tissue cooperating withanvil jaw member21 and transferring a reactionary load from the compressed tissue to forcetransducer41 substantially without a mechanical loss in a manner conducive to the mode of operation of a particular force transducer. In anembodiment compression head45 may be configured and disposed, with respect tocartridge body31, so thattissue compression face46 thereof lies substantially closer totissue contacting surface24 ofanvil jaw member21 thantissue supporting surface34 ofcartridge body31 as schematically shown inFIG. 6D showing, in a side elevation view, a tissue compressed betweencompression gauge cartridge30 andanvil jaw member21 comprising an end effector in a closed position. This is to deliberately encourage the compression of a tissue to take place preferentially over an area, out oftissue contacting surface24 of ananvil jaw member21, covered bytissue compression face46 and to minimize tissue compression overtissue supporting surface34 to a predetermined gap distance betweentissue compression face46 andtissue contacting surface24 indicated by a letter G inFIG. 6D.

In various embodiments of the presentinvention compression head45 may take on different configurations and mechanical characteristics that suit a particular application of a compression gauge cartridge of the present invention. For example, as shown inFIGS. 7B, 8B and 9B, configuration oftransducer contact face47 may be varied to accommodateforce transducer41 of different geometry, and the area and profile oftissue compression face46 may be predetermined, for example, to control the degree of tissue compression optionally in conjunction with variation of a gap distance betweentissue compression face46 andtissue contacting surface24, which is primarily controllable with aspacer member50, as will be described hereinafter. In anembodiment compression head45 may be of substantially rigid construction to be able to transfer a reactionary load imparted ontissue compression face46 thereof totransducer contact face47 without a mechanical loss even when the reactionary load is unevenly distributed overtissue compression face46. In an alternateembodiment compression head45 may be of substantially rigid construction to be able to resist deformation under a compressive load imparted thereon by the compressed tissue but otherwise of flexible nature as may be the case for a relatively thin compression head that may be employed for a force transducer of a planar configuration as schematically illustrated inFIG. 9B. In an embodiment of the presentinvention compression head45 may be configured to float, that is, be left unattached other than the mechanical engagement withforce transducer41 through transducer contact face47 thereof. In an alternateembodiment compression head45 may be fixedly joined withcartridge body31 in such a configuration that allows a displacement thereof, and concomitant deflection offorce transducer41, in response to a reactionary load from a compressed tissue to occur through a predetermined deformation ofcompression head45. In an exemplary embodiment, as previously described with reference toFIGS. 3C and 3D,compression head45 may be fixedly joined withseal member37 having sufficient flexibility to provide freedom of movement thereto. In an alternate exemplary embodiment, as shown inFIG. 8C,compression head45 may be configured and disposed to cantilever with respect to a fixedposition49 oncartridge body31 withtissue compression face46 thereof positioned remotely from fixedposition49 and transducer contact face47 positioned there-between. In another alternate exemplary embodiment,compression head45 may comprise adeformable member44 fixedly joined withcartridge body31 in a predetermined pattern, for example, along the periphery as shown inFIG. 8D schematically illustrating a cartridge body sectioned and spaced apart, and a force gauge assembly, that is configured to flex substantially perpendicularly, i.e., up and down, with respect totissue contacting surface46 ofcartridge body31.

Referring toFIGS. 3A-5B, in a preferred embodiment of the presentinvention spacer member50 may be of a rigid construction extending fromtissue supporting surface34 ofcartridge body31 disposed betweenproximal end33 anddistal end32 thereof and proximal tocompression head45 comprisingforce gauge assembly40. In anembodiment spacer member50 may be configured to be a positive stop constraining a pivotal motion of the two jaw members comprising an end effector and substantially defining the closest gap distance at the position ofspacer member50 betweentissue contacting surfaces24,26 ofanvil jaw member21 andcartridge jaw member22. In the absence of a deflection of an anvil jaw member,spacer member50 also determines a predetermined gap distance betweentissue compression face46 ofcompression head45 andtissue contacting surface24 ofanvil jaw member21 with two jaw members comprising an end effector in a fully closed position.Spacer member50 also plays an important role in substantially eliminating variation in the gap distance stemming from a play present in the pivot and drive mechanisms of a pivotal joint of the two jaw members comprising an end effector. Referring toFIGS. 10A and 10B schematically showing, in a side elevation view, a positional relationship between a cartridge jaw member represented bycompression gauge cartridge30 and an anvil jaw member in a fully closed position, in an embodiment of the present invention,spacer member50 may be dimensioned to make the two planes, substantially defined bytissue supporting surface34 andtissue contacting surface24, respectively, to be substantially parallel with each other in providing a predetermined gap distance G betweentissue compression face46 andtissue contacting surface24. In an alternateembodiment spacer member50 may be dimensioned to make the two planes to be at a predetermined angle with each other in providing a predetermined gap distance G betweentissue compression face46 andtissue contacting surface24. In a furtherembodiment spacer member50 may be dimensioned so that substantially all the plays in a pivot mechanism and a drive mechanism of a pivotal joint of the two jaw members are fully taken up when the two jaw members are in fully closed position as will be further described in the following section.

In a preferred embodiment of the present invention,spacer member50 comprisingcompression gauge cartridge30 may be a block of a rigid construction fixedly joined withcartridge body31. As shown inFIG. 11A, in anembodiment cartridge body31 andspacer member51 may be configured so that the position ofspacer member51 along the length ofcartridge body31 may be changed to suit a particular application of a compression gauge cartridge of the present invention.Spacer member50 plays a significant role in substantially eliminating variation in the positional relationship between the two jaw members comprising an end effector due to plays present in the pivot and drive mechanisms of a pivotal joint of the two jaw members by acting as a rigid fulcrum disposed between the pivot mechanism and a compression head comprising a force gauge assembly that forces the plays to be fully taken up when the two jaw members reach a fully closed and, in some cases, locked position. Even when the tissue contacting surface of the anvil jaw member comes to rest making contact with the spacer member as the two jaw members close driven by the drive mechanism, the drive mechanism continues to drive the pivot mechanism to rotate one or both of the jaw members with respect to the point of contact between the anvil jaw member and the spacer member until all the plays in the pivot and drive mechanisms are fully taken up and the pivotal motion of the two jaw members comes to a solid stop reaching a final positional relationship there-between. Since, in practice, the force involved in driving the pivotal motion of the two jaw members are, by design, much larger than the largest reactionary load normally expected from a compressed tissue between the two jaw members comprising an end effector of a surgical stapler instrument, the final positional relationship between the two jaw members thus achieved remains substantially undisturbed even when the two jaw members are acted upon from the reactionary load from a compressed tissue there-between and is solely determined by the position and configuration ofspacer member50. Barring potential deflection of the anvil jaw member under a reactionary load from a compressed tissue, which can be effectively kept under control as previously described,spacer member50 thus enables a surgical stapler instrument implemented with a compression gauge cartridge of the present invention to be used, without modification, to provide a predetermined gap distance, between the compression face of the compression head and the tissue contacting surface of the anvil jaw member, consistently and with high degree of repeatability, and concomitantly to compress a tissue consistently to a thickness corresponding to the predetermined gap distance.

In an embodiment of the present invention, a spacer member also functions as a tissue stop defining a proximal most position along the cartridge body to which a tissue can be introduced between the two jaw members comprising an end effector. Referring toFIGS. 11B and 11C, in anembodiment spacer member55,60 may further comprise aspacer extension member57,62 for preventing a portion of a tissue getting caught, while being captured, and subsequently pinched between a spacer member and a tissue contacting surface of an anvil jaw member as the two jaw members are closed. As shown inFIG. 11B, in an embodimentspacer extension member57 may be of a retractable/extendable type configured to move in and out of aspacer member body56, for example, aspring58 loaded plunger or detent biased to extend out of a cavity inspacer member body56 to a preset limit and to follow the pivotal motion of the two jaw members keeping the gap between the spacer member and the tissue contacting surface of an anvil jaw member closed. In an alternate embodiment, as shown inFIG. 11C,spacer extension member62 may be of a collapsible/expandable type including an air filled bladder, resilient foam, a metal spring element and a leaf spring element made of a stiff polymer film, etc, configured to require a minimal force to be collapsed down to aspacer member body61. Referring toFIG. 11D, in an embodiment a compression gauge cartridge may comprise aprotective cover39 providing protection, for example, undesirable impact during handling, over at least part ofcartridge body31 thereof, preferably, including the general area around the position of the force gauge assembly.

Referring toFIGS. 12A-12C showing a spacer member, and acartridge body31 and acartridge bay23 broken away and sectioned apart, in an embodiment of the present invention, a spacer member comprising a compression gauge cartridge may be configured so that the height thereof over the tissue supporting surface of the cartridge body, i.e., the vertical extent the spacer member extends from the tissue supporting surface, may be adjusted. As shown inFIG. 12A, in an embodiment of the present invention, anadjustable spacer member65 having ananvil contacting face66 may be mounted on a threadedbase67 of a gender disposed in ahole69 incartridge body31 with a matching thread of an opposite gender so that the vertical position ofanvil contacting face66 may be adjusted by turning acontrol stem68 fixedly joined with threadedbase67 and disposed through a slot normally found incartridge bay23. As shown inFIG. 12B, in an alternate embodiment, anadjustable spacer member70 having ananvil contacting face71 may comprise arigid base72 disposed in ahole75 incartridge body31 and on awedge shape platform73 joined with acontrol stem74 disposed through a slot incartridge bay23 so that the vertical position ofanvil contacting face71 may be adjusted and locked in a position by slidingcontrol stem74 along the slot. As shown inFIG. 12C, in another alternate embodiment, anadjustable spacer member76 may be configured to have a nested structure comprising astationary base77 and amovable plunger78 slidably engaged withstationary base77 in a hole81 for vertical movement with respect to the tissue supporting surface and to include at least onebreak member79 with a predetermined breaking mechanism, for example, a sharp edge, drivable with control stems80 fixedly joined therewith and disposed through a slot incartridge bay23 so thatmovable plunger78 may be securely held immobile once the desired vertical position thereof is reached. In an embodimentadjustable spacer member65,70,76 may be configured with a bias spring that drives adjustable spacer member or a movable part thereof to a final position when triggered by a predetermined event, an example of which will be described hereinafter.

As shown inFIGS. 12D and 12E, in an embodiment of the present invention aspacer member100 may be configured to include anaxle104, aspring element103 and at least oneflap member101, and to be disposed in acavity102 in a cartridge body comprising a compression gauge cartridge withaxel104 rotatably mated with a pair ofholes105 in the cartridge body so thatspacer member100 may pivot with respect to the cartridge body aroundaxle104.Spring element103 may be configured to biasspacer member100 so that it remains upright with respect to the cartridge body ready to withstand the downward load from the anvil member when the two jaw members comprising the end effector are in a fully closed position. At least oneflap member101 may be configured and disposed with respect tospacer member100 so that it may be flipped proximally and distally therewith when acted on by the proximal and distal ends of a trocar, respectively, during insertion and removal there-through of a surgical stapler instrument instrumented with the compression gauge cartridge. In anembodiment spacer member100 may be rotated to reduce the height thereof above the cartridge body, as schematically shown inFIG. 12E, manually by a physician prior to insertion of a surgical stapler instrument or automatically by the interaction thereof with the distal end of the trocar during removal of a surgical stapler instrument. A spacer member of such a configuration would enable use of a compression gauge cartridge with a spacer member so tall that would make an end effector of a surgical stapler instrument instrumented with the compression gauge cartridge impassable through a normally used trocar even with the jaw members in a fully closed position.

Surgical stapler instrument products of a design, like any other engineering products, inherently includes certain variations in their mechanical performance, which, by design, are not of significance in originally intended uses in surgical stapling operation but may negatively affect uses of a surgical stapler instrument instrumented with a compression gauge cartridge of the present invention. For example, such variations could manifest between different production lots, for example, due to change in production steps and/or even between different instruments from the same production lot, for example, due to changes in the manufacturing tolerances of parts and/or subassemblies. As described previously, changes in the plays in the pivot and drive mechanism of a surgical stapler instrument, for example, resulting from variations in manufacturing tolerances may degrade the precision in the final positional relationship between the two jaw members in a fully closed and locked position and, in turn, the predetermined gap distance between the tissue compression face of the compression head and the tissue contacting surface of the anvil jaw member corresponding to a predetermined thickness to which a tissue is compressed. To circumvent the potential impact these variations may have on the performance of a compression gauge cartridge mounted on a surgical stapler instrument or in a surgical compression gauge instrument, in various embodiments of the present invention, there are provided methods for calibrating the gap distance between the tissue compression face of the compression head and the tissue contacting surface of the anvil jaw member. Referring toFIG. 13A showing, in a side elevation view, ananvil jaw member21 and acompression gauge cartridge30 representing a cartridge jaw member, in an embodiment a gap distance calibration method comprises steps of: (1) positioning areference block85 over acompression head45 of height corresponding to a predetermined gap distance betweentissue compression face46 ofcompression head45 and thetissue contacting surface24 ofanvil jaw member21; (2) fully closing the two jaw members of the end effector; and (3) adjusting the height of anadjustable spacer member90 until the load cell indicator reads zero. In an embodiment the height ofreference block85 may be fine tuned to reflect possible deflection ofanvil jaw member21 due to a reactionary load fromreference block85 during the gap distance calibration procedure. For example,reference block85 may be made taller than a predetermined target gap distance to account for deflection ofanvil jaw member21. In an embodiment fully closing the two jaw members may involve operating a handle assembly comprising a surgical stapler instrument or a surgical compression gauge instrument to close the two jaw members until the handle assembly reaches a locked state corresponding to a limit of the closing operation. In an alternate embodiment a gap distance calibration method comprises steps of: (1)positioning reference block85 over acompression head45 of height corresponding to a predetermined gap distance betweentissue compression face46 ofcompression head45 andtissue contacting surface24 ofanvil jaw member21; (2) fully closing the two jaw members of the end effector; and (3) adjusting the height ofadjustable spacer member90 until it touchestissue contacting surface24 ofanvil jaw member21. In another alternate embodiment a gap distance calibration method comprises steps of: (1) positioning a reference material over acompression head45 of known tensile property and dimension betweentissue compression face46 ofcompression head45 andtissue contacting surface24 ofanvil jaw member21; (2) fully closing the two jaw members of the end effector; and (3) adjusting the height ofadjustable spacer member90 until the load cell indicator reads a predetermined value indicating the reference material is compressed to a thickness corresponding to a predetermined gap distance betweentissue compression face46 ofcompression head45 andtissue contacting surface24 ofanvil jaw member21. As shown inFIGS. 13B and 13C, in an embodiment of the present invention aprotective cover87 may be configured to comprise a built-inreference block88 and atrigger member91 for causing aspring92 to drive alocking mechanism73,74 foradjustable spacer member71 to facilitate the gap calibration procedure.

Referring toFIG. 14, in an embodiment of the present invention, acompression gauge cartridge30 may comprise twoparts96,97, preferably, onepart96 including aforce gauge assembly40 and theother part97 including aspacer member95, that are configured to be releasably joined with each other. In anembodiment part96 may be a part ofcompression gauge cartridge30 that can be effectively re-sterilized andpart97 difficult to re-sterilize, for example, due to internal structures present ifspacer member95 is an adjustable spacer member as previously described. After use,part96 may be kept for reuse following a re-sterilization and usedpart97 may be discarded and exchanged with a new one.

Referring toFIG. 15, in an embodiment of the present invention, a surgical compression gauge instrument110 for compressing a tissue consistently to a predetermined thickness and measure a reactionary load therefrom for assisting selection of a staple cartridge and assessing the condition of the tissue comprises: a handle portion111; a body portion112 extending distally from handle portion111 and defining a longitudinal axis; and a tool assembly120 at the distal end of and operatively connected to body portion112, tool assembly120 comprising an anvil jaw member121 having a tissue contacting surface122 and a compression gauge jaw member125, configured to open and close when operated by handle portion111, wherein compression gauge jaw member125 having a proximal end126 and a distal end127, and a tissue supporting surface128 comprises a force gauge assembly129 comprising a force transducer (not shown in the FIGURE) and a compression head130 having a tissue compression face131, supported by compression gauge jaw member125 positioned between proximal end126 and distal end127 thereof, and wherein compression head130 of force gauge assembly129 is disposed so that tissue compression face131 thereof lies substantially closer to tissue contacting surface122 of anvil jaw member121 than tissue supporting surface128 of compression gauge jaw member125; and a spacer member132 extending from tissue supporting surface128 comprising compression gauge jaw member125, wherein force gauge assembly129 is positioned distally with respect to spacer member132.

In a preferred embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance, corresponding to a height of staples contained in a predetermined cartridge from the set of standard staple cartridges, between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; comparing said reactionary load reading with a value known to be optimal for a stapling operation of said tissue to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said optimal value and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from the standard set of staple cartridges containing staples of a height corresponding to said predetermined thickness of said compressed tissue if the result of comparison is case (1), or a staple cartridge containing staples of a height smaller than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of a height larger than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In an alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined average height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance, corresponding to an average height of staples contained in a predetermined cartridge from the set of standard staple cartridges, between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; comparing said reactionary load reading with a value known to be optimal for a stapling operation of said tissue to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said optimal value and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from said standard set of staple cartridges containing staples of an average height corresponding to said predetermined thickness of said compressed tissue if the result of comparison is case (1), or a staple cartridge containing staples of an average height smaller than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of an average height larger than said predetermined thickness of said compressed tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined average height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In another alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance, corresponding to a height of staples contained in a green cartridge from the set of standard staple cartridges, between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; comparing said reactionary load reading with a value known to be optimal for a stapling operation of said tissue to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said optimal value; selecting a green cartridge from the standard set of staple cartridges if the result of comparison is case (1) or a blue cartridge if the result of comparison is case (2), or a black cartridge if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

In an alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member, of a surgical stapler instrument, a spacer member of which is configured to consistently provide a gap distance between a tissue compression face of a compression head comprising a force gauge assembly comprising said compression gauge cartridge and a tissue contacting surface of said anvil jaw member; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured between said tissue compression face and said tissue contacting surface to a predetermined thickness corresponding to said gap distance there-between; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; providing a reference tissue for which an optimal staple height for a surgical stapling operation is known; comparing said reactionary load reading with a reactionary load from said reference tissue compressed to said predetermined thickness over the same area of said reference tissue as that of said tissue compression face of said compression head to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said reactionary load from said reference tissue and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from the standard set of staple cartridges containing staples of a height known to be optimal for said reference tissue if the result of comparison is case (1), or a staple cartridge containing staples of a height smaller than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of a height larger than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

Referring toFIG. 16, showing a compression gauge cartridge30 in a perspective view in an embodiment of the present invention, compression gauge cartridge30 for use mounted in a cartridge bay of a cartridge jaw member comprising an end effector of a surgical stapler instrument, together with an anvil jaw member having a tissue contacting surface, to compress a tissue so that said cartridge jaw member and said anvil jaw member come to a predetermined angular positional relationship with each other, as indicated inFIG. 17 by a label AG in a schematic representation of an anvil jaw member21 and compression gauge cartridge30, and measure a reactionary load therefrom for assisting in selection of a staple cartridge optimal for a tissue of a surgical stapling operation comprises: a cartridge body31 having a proximal end32 and a distal end33, and a tissue supporting surface34, wherein cartridge body31 may be configured for compression gauge cartridge30 to be releasably mounted in said cartridge bay and for tissue supporting surface34 to be at least at a predetermined distance from said tissue contacting surface of said anvil jaw member when cartridge jaw member and said anvil jaw member are in a fully closed position; and a force gauge assembly40 comprising a force transducer and a compression head having a tissue compression face, wherein force gauge assembly40 may be supported by cartridge body31 positioned between proximal end32 and distal end33 thereof, and wherein said compression head comprising said force gauge assembly40 may be configured and disposed so that said tissue compression face thereof may lie substantially closer to said tissue contacting surface of said anvil jaw member than tissue supporting surface34 of cartridge body31. In an alternate embodimenttissue supporting surface34 ofcartridge body31 may be contoured in such a way to further reduce compression of a tissue disposed betweentissue supporting surface34 and said tissue contacting surface when said cartridge jaw member and said anvil jaw member are in a fully closed position.Compression gauge cartridge30 is configured to allow an existing surgical stapler instrument to be used without modification in applying a compression to a predetermined area of a tissue captured between the two jaw members comprising an end effector thereof so that the two jaw members come to a predetermined positional relationship with each other and measuring a reactionary load from the compressed area of the tissue. In an embodiment of the presentinvention cartridge body31 comprisingcompression gauge cartridge30 may be configured forcompression gauge cartridge30 to be releasably mounted and securely retained in a cartridge bay comprising a cartridge jaw member of an end effector. In an alternateembodiment cartridge body31 comprisingcompression gauge cartridge30 may be configured to be fixedly mounted in a cartridge bay to be integrated with a cartridge jaw member of an end effector of a surgical stapler instrument. In another alternateembodiment cartridge body31 comprisingcompression gauge cartridge30 may be configured to be fixedly mounted in a cartridge bay to be integrated with a cartridge jaw member of an end effector comprising a disposable reload unit of a certain surgical stapler instrument product in the market. In an alternate embodiment of the present invention the dimension of a cartridge body comprising a compression gauge cartridge may be varied to suit particular application thereof. For example, as shown inFIG. 19,cartridge body31 may be configured to be shorter than a conventional staple cartridge along the length of a cartridge bay.

Referring toFIG. 18, in an embodiment of the present invention, asurgical stapler instrument10 may further include aspacer block13 of a predetermined height disposed at ahandle11 comprisingsurgical stapler instrument10 for defining a predetermined extent handle11 may be operated to close a cartridge jaw member and an anvil jaw member comprising anend effector20 comprisingsurgical stapler instrument10 so that said cartridge jaw member and said anvil jaw member come to a predetermined angular positional relationship with each other.

In an alternate embodiment of the present invention, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation comprises steps of: mounting a compression gauge cartridge of the present invention in a cartridge bay of a cartridge jaw member comprising an end effector, together with an anvil jaw member having a tissue contacting surface, of a surgical stapler instrument; capturing a tissue between said cartridge jaw member and said anvil jaw member; closing said cartridge jaw member and said anvil jaw member to compress said tissue captured there-between so that said cartridge jaw member and said anvil jaw member come to a predetermined angular positional relationship with each other; reading out a reactionary load from said compressed tissue displayed on a force transducer indicator; providing a reference tissue for which an optimal staple height for a surgical stapling operation is known; comparing said reactionary load reading with a reactionary load from said reference tissue compressed so that said cartridge jaw member and said anvil jaw member come to said predetermined angular positional relationship with each other to determine if said reactionary load is case (1) within, case (2) below or case (3) above a window of a predetermined width around said reactionary load from said reference tissue and how large a size of difference is in cases (2) and (3); selecting a staple cartridge from the standard set of staple cartridges containing staples of a height known to be optimal for said reference tissue if the result of comparison is case (1), or a staple cartridge containing staples of a height smaller than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (2), or a staple cartridge containing staples of a height larger than that of staples known to be optimal for said reference tissue taking into account said size of difference if the result of comparison is case (3). In an alternate embodiment, a method for selecting a staple cartridge from the standard set of staple cartridges, each containing staples of a predetermined height, optimal for a tissue of a surgical stapling operation may further comprise a step of waiting for a predetermined length of time after closing said cartridge jaw member and said anvil jaw member to compress said tissue.

Referring toFIG. 20, showing acompression gauge cartridge30 in a perspective view in an embodiment of the present invention,compression gauge cartridge30 for use mounted in a cartridge bay of a cartridge jaw member comprising an end effector of a surgical stapler instrument to compress a tissue and measure a reactionary load therefrom for assisting in selection of a staple cartridge optimal for a tissue of a surgical stapling operation comprises: acartridge body31; and aforce gauge assembly40, anelectronic circuit module135 including a signal processing circuit for conditioning and digitizing a signal from saidforce gauge assembly40 and wireless transmission circuit, and abattery module136 for providing operational power to saidforce gauge assembly40 and saidelectronic circuit module135 housed in saidcartridge body31. In an embodiment, there is provided a corresponding force transducer indicator (not shown in the FIGURE) configured to receive and display a wireless signal fromcompression gauge cartridge30 indicating the result of measurement by saidforce gauge assembly40. In an embodiment saidbattery module136 may be of rechargeable type.

In an embodiment of the present invention there is provided a compression gauge cartridge comprising a cartridge body configured to allow a spacer member to be extended to and held in position at a predetermined extent or height above the tissue supporting surface of the cartridge body and retracted to or below the height required for insertion and withdrawal through a trocar of the surgical stapler instrument the end effector of which the compression gauge cartridge is mounted in. Such a compression gauge cartridge enables a surgical stapler instrument implemented therewith to probe a tissue, that is, compress a tissue and measure a reactionary load therefrom, at compressed tissue thickness that cannot be accommodated by a compression gauge cartridge with a fixed height spacer member due to constraint on the height thereof imposed by the size of a trocar through which the surgical stapler instrument must be inserted and withdrawn. Similarly, a compression gauge jaw member comprising a surgical compression gauge instrument implemented with a retractable spacer member enables the surgical compression gauge instrument to probe a tissue at thickness level that cannot be accommodated by a compression gauge jaw member with a fixed height spacer member due to constraint on the height thereof imposed by the size of a trocar through which the surgical compression gauge instrument must be inserted and withdrawn. Referring toFIG. 21 showing aspacer assembly140 and acartridge body31 comprising a compression gauge cartridge, broken away and sectioned apart, in an embodiment of the present invention,cartridge body31 may be configured to include acavity145 for housing aspacer assembly140 comprising aspacer member141, astopper142, astopper control link143, operatively joined withstopper142, and aspacer spring144.Cavity145 may comprise aspacer channel146 disposed substantially perpendicularly totissue supporting surface34 ofcartridge body31 with one end open totissue supporting surface34 for passage ofspacer member141 and the other end closed, and astopper channel147 disposed to intersectspacer channel146 substantially perpendicularly thereto in one end including apassage148 forstopper control link143 in the other end.Spacer member141 may be of rigid construction and configured to slidably engagespacer channel146 to enable smooth and substantially precise movement along the length ofspacer channel146.Stopper142 may be configured to slidably engagestopper channel147 to enable smooth and substantially precise movement along the length ofstopper channel147. Disposed inspacer channel146 between the closed end thereof andspacer member141,spacer spring144 may be configured to biasspacer member141 to move in the direction of the open end ofspacer channel146.Stopper142 may be driven bystopper control link143 to positionstopper142 in, as shown inFIG. 22A, and out, as shown inFIG. 22B, of the path ofspacer member141 inspacer channel146. In anembodiment stopper142 may be configured and constructed to provide a rigid stop tospacer member141 when positioned in the path thereof. Stopper control link143 may be operatively joined on the one end withstopper142 and on the other end with a mechanical or electronic control mechanism, preferably located on the handle of a surgical stapler instrument or a surgical compression gauge instrument, collectively referred to as the compression gauge instrument hereinafter, to be operated by the physician operator of the compression gauge instrument. In the path ofspacer member141, as shown inFIG. 22A,stopper142 rigidly holdsspacer member141 in position extended abovetissue supporting surface34 ofcartridge body31 at a predetermined height maintaining a relative positional relationship of the two jaw members of end effector of the compression gauge instrument closed to compress a tissue captured there-between. Out of the path ofspacer member141, as shown inFIG. 22B,stopper142 allowsspacer member141 to be retracted to or below a height abovetissue supporting surface34 ofcartridge body31 necessary for the two jaw members to be closed sufficiently to allow the end effector of the compression gauge instrument to pass through a trocar.

In an embodiment of the present invention, as shown inFIG. 23A,stopper152 may comprise a plurality ofsteps154,155, each corresponding to a predetermined height of the spacer member above the tissue supporting surface of the cartridge body. As show inFIG. 23B, in an exemplary embodiment,spacer member141 resting onstep155 may provide a smaller gap distance between the two jaw members of end effector of the compression gauge instrument and correspondingly a smaller compressed tissue thickness captured and compressed by the two jaw members. As shown inFIG.23C stopper152 out of the path ofspacer member141,spacer member141 may be retracted into the spacer channel to allow sufficient closure of the two jaw members for passage of the end effector and withdrawal of the compression gauge instrument through a trocar. In an embodiment of the present invention, as shown inFIG. 24,stopper162 may include asloped face164 that may allow the height of the spacer member above the tissue supporting surface of the cartridge body to be varied continuously. In an exemplary embodiment, the stopper is depicted generally of a square block shape the stopper may be of any other configuration. In an embodiment the spacer member and stopper may be further configured to include an arrangement to stop the spacer member from being ejected clear out of the spacer channel by the spacer spring. In an alternate embodiment the cavity of the cartridge body may be configured with an arrangement to stop the spacer member from being ejected clear out of the spacer channel by the spacer spring.

In an alternate embodiment of the present invention there is provided a compression gauge cartridge comprising a cartridge body configured to allow a spacer member to be extended to and held in position at a predetermined height above the tissue supporting surface of the cartridge body and retracted to or below the height required for insertion and withdrawal through a trocar of the surgical stapler instrument the end effector of which the compression gauge cartridge is mounted in. Referring toFIG. 25 showing aspacer assembly170 and acartridge body31 comprising a compression gauge cartridge, broken away and sectioned apart, in an embodiment of the present invention,cartridge body31 may be configured to include acavity175 for housing aspacer assembly170 comprising aspacer member171, astopper172, aspacer spring173 and astopper spring174.Cavity175 may comprise aspacer channel176 disposed substantially perpendicularly totissue supporting surface34 ofcartridge body31 with one end open totissue supporting surface34 for passage ofspacer member171 and the other end closed, and astopper channel177 disposed to intersectspacer channel176 substantially perpendicularly thereto in one end and closed in the other end.Spacer member171 may be of rigid construction and configured to slidably engagespacer channel176 to enable smooth and substantially precise movement along the length ofspacer channel176.Stopper172 may be configured to slidably engagestopper channel177 to enable smooth and substantially precise movement along the length ofstopper channel177. Disposed inspacer channel176 between the closed end thereof andspacer member171,spacer spring173 may be configured to biasspacer member171 to move in the direction of the open end ofspacer channel176. Disposed inspacer channel177 between the closed end thereof andstopper172,stopper spring174 may be configured to biasstopper172 to move in the direction of the open end ofstopper channel177 towardspacer channel176 normally keepsstopper172 in close contact with and/or in the path ofspacer member171 inspacer channel176 as shown inFIG. 26A.

In an embodiment aninterface179 ofstopper172 withspacer member171 may be configured so thatspacer member171 traveling downspacer channel176 toward the closed end thereof, for example, driven by closing action of the two jaw members of end effector of the compression gauge instrument, causesstopper172 to retract intostopper channel177 toward the closed end thereof as shown inFIG. 26B. Preferably, the strength or spring constant ofstopper spring174 may be such that a magnitude of force required to be applied tostopper172 by the anvil jaw member to retract stopper171 (referred to as a threshold force hereinafter) is substantially higher than that of the reactionary load from the compressed tissue between the two jaw members of the compression gauge instrument to enable the physician operator operating the compression gauge instrument by the handle to sense that the two jaw members reached a predetermined gap distance there-between corresponding to the height ofspacer member171. In the path ofspacer member171, as shown inFIG. 26A,stopper172 substantially rigidly holdsspacer member171 in position extended abovetissue supporting surface34 ofcartridge body31 at a predetermined height maintaining relative positional relationship of the two jaw members of end effector of the compression gauge instrument closed to compress a tissue captured there-between. Out of the path ofspacer member171, as shown inFIG. 26B,stopper172 allowsspacer member171 to be retracted to or below a height abovetissue supporting surface34 ofcartridge body31 necessary for the two jaw members to be closed sufficiently to allow the end effector of the compression gauge instrument to pass through a trocar. In an embodiment the spacer member and stopper may be further configured to include an arrangement to stop the spacer member from being ejected clear out of the spacer channel by the spacer spring. In an alternate embodiment the cavity of the cartridge body may be configured with an arrangement to stop the spacer member from being ejected clear out of the spacer channel by the spacer spring.

Referring toFIGS. 27 and 28A-28Cshowing spacer assemblies180,185 and acartridge body31 comprising a compression gauge cartridge, broken away and sectioned apart, in an embodiment of the present invention,cartridge body31 may be configured to include acavity191 comprisingspacer channel192 andstopper channel193 forhousing spacer assemblies180,185, as described in the preceding in relation toFIGS. 25, 26A and 26B, comprising aspacer members181,186, respectively. In an embodiment of the presentinvention spacer assemblies180,185 may be of substantially rigid construction exceptspacer members181,186 that are configured to have different lengths along the length ofspacer channel192 or different heights the difference of which corresponds to difference in the gap distance between the two jaw members separated byspacer members181,186 or corresponding difference in the tissue thicknesses captured and compressed by the two jaw members. In operation the two jaw members are first held apart at a first predetermined gap distance there-between byspacer member181 as shown inFIG. 28A. Upon application of a first threshold force by the physician operator of the compressiongauge instrument stopper182 andspacer member181 retract and the jaw members are closed to and held apart at a second predetermined gap distance byspacer member186 as shown inFIG. 28B. Upon further application of a second threshold force by thephysician operator stopper187 retracts andspacer members181,186 are free to be retracted for further closure of the two jaw members in preparation for withdrawal of the compression gauge instrument through a trocar as shown inFIG. 28C.

Referring toFIG. 29 showing aspacer assembly200 and acartridge body31 comprising a compression gauge cartridge, broken away and sectioned apart andFIG. 30 showing spacer assembly in an exploded view, in an embodiment of the present invention,cartridge body31 may be configured to include acavity209 forhousing spacer assembly200 comprising aspacer member201, astopper stack206 comprising at least onestopper207, operatively joined with astopper control link204, stacked on top of one another and astopper spring208, and aspacer spring205.Cavity209 may comprise aspacer channel210 disposed substantially perpendicularly totissue supporting surface34 ofcartridge body31 with one end open totissue supporting surface34 for passage ofspacer member201, and a portion of the other end open to astopper channel211 and the rest of the other end closed, andstopper channel211 disposed to intersectspacer channel210 substantially perpendicularly thereto closed in one end that may includepassages212 forstopper control link204 in the other end.Spacer member201 may be configured to slidably engagespacer channel210 to enable smooth and substantially precise movement along the length ofspacer channel210.Stopper207 may be configured to slidably engagestopper channel211 to enable smooth and substantially precise movement along the length ofstopper channel211. Disposed inspacer channel210 between the closed portion of the end thereof oppositetissue supporting surface34 andspacer member201,spacer spring205 may be configured to biasspacer member201 to move in the direction of the open end ofspacer channel210. In anembodiment spacer member201 may be of rigid construction and comprises aspacer body202 and aspacer stem203 fixedly joined therewith facing the closed end ofspacer channel210. In anembodiment stopper207 may be of substantially planar shape of a predetermined thickness and of rigid construction capable of supporting and substantially precisely maintainingspacer member201 in position under a load from the anvil jaw member. Preferably the length ofspacer stem203 may be configured to be equal to or longer the combined thickness ofstoppers207.Stopper207 comprises a throughhole209 dimensioned to receivespacer stem203 ofspacer member201 and, in an embodiment, at least onestoppers207 are stacked initially with throughholes209 aligned with one another. Sliding movement ofstopper207 instopper channel211 may be controlled bystopper control link204 in similar fashion to howstopper142 is controlled bystopper control link143 as described previously referring toFIG. 21. In anembodiment stopper207 may be biased bystopper spring208 to return to initial position, as described inFIG. 30 in an embodiment, following a control motion applied tostopper207 bystopper control link204. In an embodiment operation ofspacer assembly200 is described hereinafter referring toFIGS. 31A-31C. Initially,stoppers207 comprisingstopper stack206 may be disposed with throughholes209 aligned with one another but not withspacer stem203 ofspacer member201 as shown inFIG. 31A rigidly supporting and holdingspacer body202 in position at a predetermined vertical extent or height above the tissue supporting surface of the cartridge body even under a load from the anvil jaw member. In next step the physician operator operates onstopper control link204 joined with the top most, i.e., the one in contact withspacer stem203 ofspacer member201 to position throughhole209 thereof to be aligned withspacer stem203 as shown inFIG. 31B in an embodiment. Under a load from the anvil jaw member spacer stem203 ofspacer member201 falls into throughhole209 of the topmost stopper207 and spacer stem203 now rests on the second to the topmost stopper207 and the vertical extent or height thereof above the tissue supporting surface of the cartridge body is reduced by the thickness of the topmost stopper207. In an embodiment similar operation by the physician operator may be performed on the second to the topmost stopper207 to further reduce the vertical extent or height ofspacer body202 above the tissue supporting surface of the cartridge body by the thickness thereof as shown inFIG. 31C.

Referring toFIG. 32 showing agap sensor220 and acartridge body31 comprising a compression gauge cartridge broken away and sectioned apart andFIG. 33showing gap sensor220 in an exploded view, in an embodiment of the present invention,cartridge body31 may be configured to include acavity221 having at least one throughhole222 in the tissue supporting surface ofcartridge body31 forhousing gap sensor220 for providing an electrical signal indicative of the gap distance or angular positional relationship between the two jaw members of end effector of a surgical stapler instrument instrumented with the compression gauge cartridge or a surgical compression gauge instrument. In an embodiment, as shown in detail inFIG. 33,gap sensor220 may comprise asensor housing213, made up of electrically conducting material, with ahousing electrode215 attached thereto including at least oneelongated chamber214, disposed substantially perpendicularly to the tissue supporting surface of the cartridge body and having an opening substantially aligned with at least one throughhole222, for receiving aplunger assembly216. In anembodiment plunger assembly216 may comprise apiston218, preferably configured to slidably engageelongated chamber214 to enable smooth and substantially precise movement along the length thereof, apiston extension217, apiston spring219 and apiston electrode223. As shown inFIG. 34, in anembodiment piston218 may be configured to have an electricallyconducting piston core224 lined by anelectrical insulation225 along the perimeter thereof to electrically isolatepiston core224 fromsensor housing213. In anembodiment piston spring219 is disposed betweenpiston electrode223 andpiston218 and configured to biaspiston218 in the direction of the tissue supporting surface normally keepingpiston core224 ofpiston218 in electrical contact withsensor housing213. Preferably,piston spring219 may be made of electrically conducting material in order to establish an electrical connection betweenpiston core224 andpiston electrode223, and complete a circuit fromhousing electrode215 topiston electrode223.

In anembodiment piston extension217 may be configured to extend frompiston218 passing through the opening inchamber214 and at least one throughhole222 and protrude above the tissue supporting surface ofcartridge body31 to a predetermined height, and constructed to be substantially rigid to be able to conduct a load from the anvil jaw member topiston218 as the two jaw members of the compression gauge instrument are being closed. Preferably,piston extension217 may be made of electrically non-conducting material to electrically isolatepiston core224 from the anvil jaw member conventionally made of metal. As the closing anvil jaw member reaches and begins to depresspiston extension217piston core224 detaches fromhousing213 breaking off electrical contact betweenhousing electrode215 andpiston electrode223 generating an electrical signal in the form of broken electrical continuity just like an ordinary electrical switch being turned off. Preferably, the strength or spring constant ofpiston spring219 may be such that a magnitude of force required to bepiston extension217 by the anvil jaw member to forcepiston218 to retract is substantially higher than that of the reactionary load from the compressed tissue between the two jaw members of the compression gauge instrument to enable the physician operator operating the compression gauge instrument by the handle to sense that the two jaw members reached a predetermined gap distance there-between corresponding to the height ofpiston extension217. The generated signal indicates that the two jaw members reached a predetermined gap distance there-between corresponding to the predetermined height ofpiston extension217. In an embodiment there is provided agap sensor220, capable of generating signals at a plurality of predetermined gap distances between the two jaw members, comprising a plurality ofpiston assemblies216 withpiston extension217 of different height from one another. It is to be understood thatgap sensor220 represents but one exemplary embodiment of a sensor configuration relying on electrical switching for sensing a gap distance between the two jaw members. Numerous other configurations of electrical switch, well known to those of skill in the art, may be employed to construct a gap sensor for generating electrical signal indicative of the gap distance between the two jaw members. In an embodiment an electrical switch gap sensor may be configured to generate signal in the form of established electrical continuity, i.e., just like an electric switch being turned on. In an embodiment a gap sensor may be configured to generate an electrical or electronic signal varying continuously to correspond to continuous change in the gap distance between the two jaw members being closed. In an embodiment there is provided a processor for receiving and processing a signal from a gap sensor and a signal from the force transducer comprising the compression gauge cartridge and producing correlated set of data representative of gap distance and reactionary loads from the compressed tissue, and a display for presenting the results. In an alternate embodiment the processor may be further provided with capability to project a reactionary load at a predetermined gap distance, outside the capability of the compression gauge instrument, based on the correlated data set and known mechanical properties of the subject tissue.

Referring toFIG. 35 showing in perspective view agap sensor230 and acartridge body31 comprising a compression gauge cartridge broken away and sectioned apart andFIG. 36 showing in perspectiveview gap sensor230 in detail, in an embodiment of the present invention,cartridge body31 may be configured to include acavity231 having a throughhole232 in the tissue supporting surface ofcartridge body31, disposed substantially perpendicularly to the tissue supporting surface ofcartridge body31, forhousing gap sensor230 for providing electrical signals indicative of the gap distance or angular positional relationship between the two jaw members of end effector of a surgical stapler instrument instrumented with the compression gauge cartridge or a surgical compression gauge instrument comprising a compression gauge jaw member comprisinggap sensor230. In an embodiment, as shown in detail inFIG. 36,gap sensor230 may comprise apiston233, made up of electrically conducting material and preferably configured to slidably engagecavity231 to enable smooth and substantially precise movement along the length thereof, apiston spring234, made up of electrically conducting material, apiston electrode235, and apiston extension236, made up of electrically non-conducting or insulating material. There are provided at least onesensor electrode237,238 disposed immediately adjacent tocavity231 arranged such thatpiston233 comes into electrical contact therewith during movement incavity231. In anembodiment piston spring234 is disposed betweenpiston electrode235 andpiston233 to provide an electrical contact there-between and configured to biaspiston233 in the direction of the tissue supporting surface normally keepingpiston233 separated and electrically isolated fromsensor electrodes237,238. In an embodiment the position of the first point of contact ofsensor electrode237, disposed closest topiston233, withpiston233 is predetermined, withpiston extension236 of predetermined dimension in the direction of piston movement, to correspond to a first predetermined gap distance between the two jaw members of a surgical stapler instrumented with the compression gauge cartridge or a surgical compression gauge instrument. In an embodiment the distance between the first points of contact of two neighboring sensor electrodes is predetermined to correspond to incremental difference between two predetermined gap distances between the two jaw members of a surgical stapler instrumented with the compression gauge cartridge or a surgical compression gauge instrument.

In anembodiment piston extension236 may be configured to extend frompiston233 passing throughhole232 and protrude above the tissue supporting surface ofcartridge body31 to a predetermined height, and constructed to be substantially rigid to be able to transfer a load from the anvil jaw member topiston233 as the two jaw members of end effector are being closed. Preferably,piston extension236 may be made of electrically non-conducting material to electrically isolatepiston233 from the anvil jaw member conventionally made of metal. As the closing anvil jaw member reaches and begins to depresspiston extension236piston233 slides downcavity231 to reachsensor electrode237 disposed closest topiston233, withpiston spring234 in fully extended position, making electrical contact therewith and generating an electrical signal in the form of electrical continuity betweenpiston electrode235 andsensor electrode237 just like an ordinary electrical switch being turned on. The generated signal indicates that the two jaw members reached a first predetermined gap distance there-between corresponding to the position of the first point of contact ofsensor electrode237. As the anvil jaw continues to closepiston233 reachessensor electrode238, disposed second closest topiston233, making electrical contact therewith and generating an electrical signal in the form of electrical continuity betweenpiston electrode235 andsensor electrode238. The generated signal indicates that the two jaw members reached a second predetermined gap distance there-between corresponding to the position of the first point of contact ofsensor electrode238.

Referring toFIG. 37 showing in perspective view agap sensor240 and acartridge body31 comprising a compression gauge cartridge broken away and sectioned apart andFIG. 38 showing in perspectiveview gap sensor240 in detail, in an embodiment of the present invention,cartridge body31 may be configured to include acavity241 having a throughhole242 in the tissue supporting surface ofcartridge body31, disposed substantially perpendicularly to the tissue supporting surface ofcartridge body31, forhousing gap sensor240 for providing electrical signal indicative of the gap distance or angular positional relationship between the two jaw members of end effector of a surgical stapler instrument instrumented with the compression gauge cartridge or a surgical compression gauge instrument comprising a compression gauge jaw member comprisinggap sensor240. In an embodiment, as shown in detail inFIG. 38,gap sensor240 may comprise aforce transducer243 housed incavity241 and asensor spring244 disposed to rest on the sensitivity or loading area offorce transducer243, where a load to be measured needs to be applied to, on the one end and to extend via throughhole242 above the tissue supporting surface on the other end, which is configured to come in contact with and be depressed by the anvil jaw member as the two jaw members are closed. In anembodiment sensor spring244 may be calibrated to exert a load, to a predetermined precision, to the loading area offorce transducer243 proportional to change in length thereof occurring when depressed by the closing anvil jaw member. Preferably, there is provided a processor, to which the output signal offorce transducer243 is connected to, which is configured to analyze the output signal and extract corresponding gap distance between the two jaw members for display. In anembodiment sensor spring244 may be substituted with other elastic element calibrated to exert a load onforce transducer243 proportional to change in a dimension thereof occurring when depressed by the anvil jaw member.

Referring toFIG. 39 showing in perspective view agap sensor250 and acartridge body31 comprising a compression gauge cartridge broken away and sectioned apart andFIG. 40 showing in explodedview gap sensor250 in detail, in an embodiment of the present invention,cartridge body31 may be configured to include acavity251 including anelongated chamber252 with one end closed and the other open to the tissue supporting surface ofcartridge body31 and disposed substantially perpendicularly to the tissue supporting surface ofcartridge body31 forhousing gap sensor250 for providing electrical signals indicative of the gap distance or angular positional relationship between the two jaw members of end effector of a surgical stapler instrument instrumented with the compression gauge cartridge or a surgical compression gauge instrument comprising a compression gauge jaw member comprisinggap sensor250. In an embodiment, as shown in detail inFIG. 40,gap sensor250 may comprise apotentiometer253, atransmission assembly254, apiston assembly255 comprising apiston256 of elongated and rigid construction, and arack gear257 fixedly joined withelongated piston256 substantially along the length thereof, and apiston spring258. Preferablypiston256 may be configured to extend past the open end ofchamber252 above the tissue supporting surface ofcartridge body31 to a predetermined extent sufficient to come in contact with the anvil jaw member at a predetermined gap distance between the two jaw members and to slidably engagechamber252 to enable smooth and substantially precise movement along the length thereof when depressed by the anvil jaw member as the two jaw members are closed or urged bypiston spring258 toward the anvil jaw member.Piston assembly255 is biased bypiston spring258, disposed inchamber252 between the closed end thereof andpiston256, to move in the direction of the open end ofchamber252. In anembodiment transmission assembly254 comprises a set of gears including a pinion gear for engagingrack gear257 for converting linear motion ofpiston assembly255 into a circular motion and a gear combination for amplifying the motion ofpiston assembly255 and transferring the result of amplification in a rotary motion topotentiometer253, well known to those of skill in the art, which is configured to convert an input rotary motion into an output voltage signal of magnitude proportional to the degree of input rotary motion. Preferably, there is provided a processor, external to the compression gauge cartridge or the surgical compression gauge instrument, for receiving and processing the output voltage signal to provide an output corresponding to the distance travelled bypiston assembly255 from which the gap distance between the two jaw members at any given point in time can be extracted.

Referring toFIG. 41 showing acompression gauge cartridge261 and ananvil jaw member262, having atissue contacting surface264, comprising anend effector260 of a surgical stapler instrument instrumented withcompression gauge cartridge261 disposed in the cartridge bay of the cartridge jaw member thereof, in an embodiment of the present invention, atissue supporting surface263 ofcompression gauge cartridge261 may be configured to minimize compression of tissue captured between the two jaw members ofend effector260 outside the area covered by the tissue compression face of the compression head comprising the force gauge assembly comprisingcompression gauge cartridge261 whiletissue contacting surface264 ofanvil jaw member262 may be configured to be substantially flat without special features thereon for reducing tissue compression. Similarly, in an embodiment, a tissue supporting surface of the compression gauge jaw member of a surgical compression gauge instrument may be configured to minimize compression of tissue captured between the two jaw members of end effector outside the area covered by the tissue compression face of the compression head comprising the force gauge assembly comprising the compression gauge jaw member while the tissue contacting surface of the anvil jaw member may be configured to be substantially flat without special features thereon for reducing tissue compression. In an alternate embodiment, as shown inFIGS. 42A and 42B, atissue supporting surface266 ofcompression gauge cartridge261 may be configured to be substantially flat without special features thereon for reducing tissue compression andtissue contacting surface264 ofanvil jaw member262 may be configured to include ananvil compression head265 of a predetermined shape configured to extend fromtissue contacting surface264 ofanvil jaw member262 to minimize compression of tissue captured between the two jaw members ofend effector260 outside the area covered by the tissue compression face of the compression head. Preferably, the area over whichanvil compression head265 comes into contact with tissue is substantially equal to or larger than that of the tissue compression face of the compression head comprising the force gauge assembly comprisingcompression gauge cartridge261. In another alternate embodiment, as shown inFIG. 43, atissue supporting surface263 ofcompression gauge cartridge261 may be configured to minimize compression of tissue captured between the two jaw members ofend effector260 outside the area covered by the tissue compression face of the compression head andtissue contacting surface264 ofanvil jaw member262 may also be configured to include ananvil compression head267 of a predetermined shape configured to extend fromtissue contacting surface264 ofanvil jaw member262 to minimize compression of tissue captured between the two jaw members ofend effector260. Preferably, the area over whichanvil compression head267 comes into contact with tissue is substantially equal to or larger than the area of the tissue compression face of the compression head comprising the force gauge assembly comprisingcompression gauge cartridge261. In an embodiment of the present invention, as shown inFIG. 44, aspacer273 may be disposed onanvil jaw member272 and not oncompression gauge cartridge271 comprising anend effector270. Similarly, in an embodiment, a spacer may be disposed on the anvil jaw member and not on the compression gauge jaw member comprising an end effector.

Referring toFIGS. 45A and 45 B showing in perspective view an adjustable andretractable spacer assembly260 and acartridge body31 comprising a compression gauge cartridge partially broken away and partially broken away, sectioned and spaced apart, respectively, andFIG. 46 showing in perspectiveview spacer assembly260 in detail, in an embodiment of the present invention,cartridge body31 may be configured to include acavity261 open to the tissue supporting surface ofcartridge body31, disposed substantially perpendicularly to the tissue supporting surface ofcartridge body31, forhousing spacer assembly260 for providing a rigid stop for maintaining a predetermined gap distance or angular positional relationship between the two jaw members of end effector of a surgical stapler instrument instrumented with the compression gauge cartridge or a surgical compression gauge instrument comprising a compression gauge jaw member comprisingspacer assembly260. In anembodiment cavity261 may be configured to slidably engagespacer assembly260 to enable smooth and substantially precise movement ofspacer assembly260 therein substantially perpendicularly to the tissue supporting surface ofcartridge body31. In an embodiment, as shown in detail inFIG. 46,spacer assembly260 may comprise aspacer member264 of rigid construction having a threadedportion265 of a gender, athumb wheel266 having a throughhole267 with amatching thread268 of opposite gender to that of threadedportion265 for receivingspacer member264 with threadedportion265 rotatably engagingmatching thread268 and aspacer spring269. Preferably,thumb wheel266 may be configured to be partially exposed through aside263 ofcartridge body31 to allow manipulation by a physician operator. Preferably spacermember264 may be configured to extend past the opening ofcavity261 above the tissue supporting surface ofcartridge body31 to a predetermined extent sufficient to come in contact with the anvil jaw member at a predetermined gap distance between the two jaw members andspacer spring269 may be disposed to biasspacer assembly264 to move in the direction of the opening ofcavity261. In an embodiment the distance above the tissue supportingsurface spacer member264 extends may be adjusted by turningthumb wheel266 which drivesspacer member264 up and downcavity261 via the rotatable, threaded engagement betweenthumb wheel266 andspacer member264. Whenspacer member264 is depressed by the anvil jaw member as the two jaw members are closed or urged byspacer spring269 toward the anvil jawmember spacer assembly260 moves alongcavity261 smoothly and substantially precisely allowing spacerassembly260 to be retracted intocavity261, preferably, sufficiently for the two jaw members comprising end effector to be closed and be able to pass through a trocar. Preferably, the strength or spring constant ofspacer spring269 may be such that a magnitude of force required to be applied tospacer member264 by the anvil jaw member to causespacer assembly260 to retract is substantially higher than that of the reactionary load from the compressed tissue between the two jaw members of the compression gauge instrument to enable the physician operator to be able sense that the two jaw members reached a predetermined gap distance corresponding to the extent or height ofspacer member264 above the tissue supporting surface ofcartridge boy31.

In an embodiment of the present invention there is provided a surgical instrument with an end effector comprising a pair of jaw members pivotally engaged with each other through a pivot mechanism, which open and close when driven by a drive mechanism associated with handle operated by a physician, for example, to capture a tissue there-between, with one of the jaw members instrumented with a spacer assembly comprising a spacer member and a base or a spacer base for maintaining a predetermined gap distance or relative angular positional relationship between the two jaw members when the two jaw members are closed. In an embodiment one of the two jaw members comprising the end effector of the surgical instrument may be an anvil jaw member and the other a compression gauge jaw member comprising a spacer assembly and a force gauge assembly comprising a force transducer and a compression head. The surgical instrument may further comprise a mechanism for controlling the position of the spacer base that may be operated by a physician to select the gap distance between the two jaw members.

Referring toFIGS. 47 and 48 showing, in an embodiment of the present invention, asurgical instrument300 in perspective view and a surgical instrument partially sectioned and spaced apart, respectively, for use in a surgical operation,surgical instrument300 may comprise ahandle301, anelongated shaft302 extending distally fromhandle301 and having a proximal end and a distal end, anend effector303 supported byelongated shaft302 at distal end thereof and comprising a pair ofjaw members303a,303bpivotally engaged with each other, a spacer base control mechanism or abase control mechanism304, and a signal processor anddisplay unit305 disposed proximally to handle301 and at the proximal end ofelongated shaft302. In an embodiment of the present invention one of the twojaw members303a,303bmay be configured as a compression gauge jaw member instrumented with a force gauge assembly and a spacer assembly, and theother jaw member303bmay be configured as an anvil jaw member. In an embodiment the surgical instrument may further comprise arotation wheel306 fixedly joined coaxially withelongated shaft302 andelongated shaft302 may be configured to rotate with respect to handle301 so that a physician may rotateelongated shaft302 along withend effector303, spacerbase control mechanism304 and signal processor anddisplay unit305 about the axis or the length direction ofelongated shaft302 to aid in application of the surgical instrument. In an embodimentelongated shaft302 may comprise a bendable section operably connected with a bending control mechanism inhandle301 to allow articulation ofend effector303 to aid in application of the surgical instrument. As shown inFIG. 48 and in detail inFIG. 49 in an embodiment of the presentinvention end effector303 may be operably connected withhandle301 by an end effector control link307 disposed inelongated shaft302, which transfers the actuation force applied to handle301 by a physician or a power driven actuator (seeFIG. 65) in operating handle301 to open or close the twojaw members303a,303bcomprisingend effector303. As shown inFIG. 48 and in detail inFIG. 50 in an embodiment of the present invention spacerbase control mechanism304 may be operably connected with aspacer base313 comprising a spacer assembly (for example, seeFIGS. 54-56) by a spacer base control link308 disposed inelongated shaft302, which transfers the actuation force applied to spacerbase control mechanism304 by a physician or a power driven actuator (seeFIG. 65) in operating spacerbase control mechanism304 to manipulate the position ofspacer base313. In an embodiment spacerbase control mechanism304 includes aguide member310 for guiding spacerbase control link308. Detailed descriptions of various embodiments of spacer base control mechanism are provided later in this Detailed Description. As shown inFIG. 50 and in detail inFIG. 51, in an embodiment of the present invention, signal processor anddisplay unit305 comprises adisplay screen312 and anelectronic circuit board311 which may be electrically connected with aforce transducer314 by a signal cable including a plurality of conductors or electrical lines for receiving output signals from and supplying power needed in operatingforce transducer314. In an embodimentelectronic circuit board311 may be configured to accommodate various electronic components including a signal processor or CPU required to process output signals fromforce transducer314 and to drivedisplay screen312, and to control power driven actuators for operatinghandle301 and/or spacer base control mechanism304 (seeFIG. 65). In an embodiment the CPU may display various information produced in the course of signal processing and power driven actuator control ondisplay screen312 and/or on a remote display screen, for example, via wireless link. In an embodiment an electrical power needed in operatingelectronic circuit board311 may be housed signal processor anddisplay unit305 in the form of one or more batteries. In an alternate embodiment an electrical power may be supplied from an external power source (not shown in the FIGURES).

Referring toFIGS. 52 and 53 showing, in an alternate embodiment of the present invention, asurgical instrument300 in perspective view and a surgical instrument partially sectioned and spaced apart, respectively, for use in a surgical operation,surgical instrument300 may comprise a spacerbase control mechanism315 disposed distally to handle301 and having aboss316 for fixedly attaching spacerbase control link308, and a signal processor anddisplay unit305 associated withhandle301. In an embodiment spacerbase control mechanism315 may be configured as a collar slidably disposed along and aroundelongated shaft302 disposed at a predetermined position along the length thereof. InFIGS. 52 and 53 the same reference characters are used as inFIGS. 47-51 to identify like elements. In an embodiment a physician operates spacerbase control mechanism315 by sliding back and forth along the length ofelongated shaft302 to impart a linear driving force to spacerbase control link308. In an embodiment the surgical instrument may further comprise a rotation wheel fixedly joined coaxially withelongated shaft302 andelongated shaft302 may be configured to rotate with respect to handle301 so that a physician may rotateelongated shaft302 along withend effector303 and spacerbase control mechanism304 about the axis or the length direction ofelongated shaft302 to aid in application of the surgical instrument.

In a practical implementation of a spacer assembly described previously with reference toFIGS. 21-24,FIG. 54 shows, in perspective view, aspacer assembly321 disposed in a compressiongauge jaw member303a, shown partially broken, sectioned and spaced apart, comprising an end effector comprising a surgical instrument in an embodiment of the present invention, andFIG. 55 shows, in perspective view,spacer assembly321 in detail. As shown inFIG. 54, in an embodiment, compressiongauge jaw member303amay be configured to include acavity322 open to atissue supporting surface323 thereof forhousing spacer assembly321 for providing a rigid stop top to maintain a predetermined gap distance or angular positional relationship between the anvil and compression gauge jaw members comprising the end effector. In an embodiment, as shown in detail inFIG. 55,spacer assembly321 may comprise aspacer member325 of rigid construction, aspacer base326, referred to as a stopper in describingFIGS. 21-24, of rigid construction operatively joined with spacerbase control link308 and configured to supportspacer member325 on a steppedside327 thereof with each step corresponding to a discrete height ofspacer member325 abovetissue supporting surface323 ofjaw member303a, and spacer springs328. In an alternate embodiment, as shown inFIG. 56,spacer base331 may be configured to supportspacer member330 on asloped side332 to allow the height ofspacer member325 abovetissue supporting surface323 ofjaw member303ato be varied continuously. In an embodiment of the presentinvention spacer member325,330 andcavity322 may be configured to allowspacer member325,330 to move smoothly and substantially precisely in direction substantially perpendicular totissue supporting surface323 ofjaw member303aandspacer base326,331 andcavity322 may be configured to allowspacer base326,331 to move smoothly in direction substantially perpendicular tospacer member325,330 and parallel totissue supporting surface323 ofjaw member303a. In an embodiment spacer springs328 are configured to biasspacer member325,330 toward the anvil jaw member (not shown inFIG. 54). In an embodiment spacerbase control link308 may be directly joined with and configured to transfer a linear actuation force provided by a spacer base control mechanism to drivespacer base326,331 to move back and forth substantially linearly and parallel totissue supporting surface323 ofjaw member303ato change the position ofspacer base326 with respect tospacer member325. In an alternate embodiment spacerbase control link308 may be operably joined withspacer base326,331 via a motion conversion means to convert, for example, an actuation force transferred via spacer base control link308 from rotation to linear form, to drivespacer base326,331 to move back and forth substantially parallel totissue supporting surface323 ofjaw member303a. In anembodiment spacer assembly321 may include a spring for biasingspacer base326,331 toward or away from spacerbase control link308. Spacer assemblies shown inFIG. 12A andFIGS. 45B and 46 are some of exemplary embodiments of spacer assembly requiring a rotation of a spacer base to adjust the height of the spacer member above the tissue supporting surface of a jaw member in which the spacer assembly is housed. Spacer assembly shown inFIGS. 29 and 31C is an exemplary embodiment of spacer assembly requiring a plurality of spacer base control links to adjust the height of the spacer member above the tissue supporting surface of a jaw member in which the spacer assembly is housed.

Referring toFIGS. 57 and 50, in an embodiment of the present invention, spacerbase control link308, having aproximal end335 and adistal end336, may be of any configuration and construction suitable for transfer of actuation force imparted thereto by a spacerbase control mechanism304, which will be described later in this Detailed Description. In an embodiment spacerbase control link308 may comprise at least one flexible wire, at least one rigid rod, at least one hydraulic or pneumatic line, at least one threaded rod, at least one rigid bar, at least one bar flexible lengthwise or a combination thereof with proximal anddistal end335,336 of spacer base control link308 configured to operably engage a spacer base control mechanism and a spacer base, respectively. For example, in an embodiment,proximal end335 of spacerbase control link308 may be configured or terminated with acam follower337 to operably engage a spacer base control mechanism based on a cam driving mechanism, for example, as illustrated inFIG. 59. In an embodimentdistal end336 may be terminated with a force conversion mechanism before being operably joined with a spacer base including a screw on a threaded shaft, a worm gear drive, a rack and pinion gears, a crank mechanism or a cam drive mechanism to convert a linear actuation force transferred via spacerbase control link308 to a rotational actuation force and vice versa, which is then applied to the spacer base. In an embodiment actuation force provided by a spacer base control mechanism that may be transferred by spacerbase control link308 may include a linear force, i.e., push and/or pull force, a rotational force or a fluid pressure. As shown inFIG. 58 spacerbase control link340 may comprise acore link element341, for example, a flexible wire, a rigid rod, a threaded rod, a rigid bar, a bar flexible lengthwise housed in atubular housing342. Preferably,tubular housing342 may be constructed to be able to maintain a constant length with two ends thereof fixedly joined with a spacer base control mechanism and a jaw member instrumented with a spacer assembly, for example, a compression gauge jaw member, respectively. In an embodimenttubular housing342 may be flexible so that spacerbase control link340 may be used in an elongated shaft with a bendable section comprising the surgical instrument of the present invention. In an alternate embodimenttubular housing342 may be rigid.

Referring toFIG. 59 showing in perspective view a spacerbase control mechanism345 based on a cam drive mechanism, sectioned and spaced apart, in an embodiment of the present invention, spacerbase control mechanism345 may comprise athumbwheel346 having arotation axis348 disposed substantially perpendicularly to the length direction of spacerbase control link308 and acam groove347 configured to receive acam follower349 of spacerbase control link308. In anembodiment cam groove347 may be designed in such a way that rotation ofthumbwheel345 drivescam follower349 linearly along the length of spacerbase control link308, which may be guided byguide member310 as shown inFIG. 50. In anembodiment cam groove347 may be designed to apply a pull force to spacerbase control link308 when rotated in a predetermined direction. In anembodiment cam groove347 may be designed to apply a pull force to spacerbase control link308 when rotated in a predetermined direction and a push force in opposite direction. Referring toFIG. 60 showing in perspective view a spacerbase control mechanism350 based on a slider-crank mechanism, sectioned and spaced apart, in an alternate embodiment of the present invention, spacerbase control mechanism350 may comprise athumbwheel351 having arotation axis354 disposed substantially perpendicularly to the length direction of spacerbase control link308 and a crank353 pivotally joined with apivot352 disposed onthumbwheel351 on one end and spacer base control link308 on the other end. In anembodiment pivot352 may be disposed onthumbwheel351 in such a way that rotation ofthumbwheel351 drives spacer base control link308 linearly along the length thereof. In anembodiment pivot352 may be disposed to apply a pull force to spacerbase control link308 when rotated in a predetermined direction. In anembodiment pivot352 may be disposed to apply a pull force to spacerbase control link308 when rotated in a predetermined direction and a push force in opposite direction. Referring toFIG. 61 showing in perspective view a spacerbase control mechanism355 based on a rack and pinion gears, in an alternate embodiment of the present invention, spacerbase control mechanism355 may comprise athumbwheel356 having arotation axis359 disposed substantially perpendicularly to the length direction of spacerbase control link308, a pinion gear385 disposed coaxially withrotation axis359 and arack gear357 fixedly joined with spacerbase control link308. Spacerbase control mechanism355 is capable of providing a pull and push force to spacer base control link308 depending on the direction of rotation ofthumbwheel356 effectively converting rotational actuation force to linear actuation force.

Referring toFIG. 62 showing in perspective view a spacerbase control mechanism360 based on a thumbwheel drive, in an embodiment of the present invention, spacerbase control mechanism360 may comprise athumbwheel361 with rotation axis disposed substantially in line with the length direction of spacer base control link308 fixedly joined therewith. Rotation ofthumbwheel361 directly imparts a rotation actuation force to spacerbase control link308. Referring toFIG. 63 showing in perspective view a spacerbase control mechanism365 based on a screw drive, in an embodiment of the present invention, spacerbase control mechanism365 may comprise athumbwheel366 with rotation axis disposed substantially in line with the length direction of spacerbase control link308 and a threaded hole disposed coaxially therewith. In an embodiment spacerbase control link308 may be terminated with a threadedrod end367 with thread matching that of thread hole inthumbwheel366 to be mated therewith. Rotation ofthumbwheel366 causes a linear motion of spacerbase control link308 through threadedrod end367. Referring toFIG. 64 showing in perspective view a spacerbase control mechanism370 based on a worm drive, in an embodiment of the present invention, spacerbase control mechanism370 may comprise aworm372 and aworm gear371 with rotation axis disposed in line with spacerbase control link308. Rotation ofworm372 causesworm gear371 to rotate rotationally driving spacerbase control link308.

Referring toFIG. 65 showing, in an embodiment of the present invention, asurgical instrument375 in perspective view, partially sectioned and spaced apart, for use in a surgical operation,surgical instrument375 may comprise ahandle376, anelongated shaft377 extending distally fromhandle376 and having a proximal end and a distal end, an end effector (not shown inFIG. 65) supported byelongated shaft377 at distal end thereof and controlled by end effector control link307 configured to be driven by powered actuators, for example, by electrical motor, a spacerbase control mechanism378 configured to be driven by powered actuators, for example, by electrical motor to actuate spacerbase control link308, and a signal processor anddisplay unit379. In an embodiment of the present invention the powered actuators driving endeffector control link307 and spacerbase control link308 may be controlled by the CPU housed in signal processor anddisplay unit379, which also may process output signals from the force transducer from a compression gauge jaw member instrumented therewith and drive the display screen. In an embodiment signal processor anddisplay unit379 may be provided with programmable capabilities to coordinate controls of the end effector and the spacer base comprising the spacer base assembly with the results of processing of output signals from the force transducer.

Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated materials does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

While preferred illustrative embodiments of the invention are described above, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the invention. Accordingly, the appended claims should be used to interpret the scope of the present invention.

Claims (19)

What is claimed is:

1. A surgical instrument for assessing a mechanical property of tissue under compression comprising:

a handle;

an elongated shaft disposed distally and operably coupled to said handle;

an end effector disposed distally and operably coupled to said elongated shaft, said end effector comprising:

a first jaw member and a second jaw member pivotally joined for pivotal motion with respect to each other to open and close when operated by said handle to capture and compress said tissue there-between;

an adjustable spacer assembly comprising an adjustable spacer member and a spacer base disposed on said first jaw member;

a control mechanism supported by said elongated shaft and disposed adjacent to said handle for producing an actuation force; and

at least one control link having a first end and a second end, disposed in said elongated shaft operably engaged with said control mechanism and said spacer base comprising said adjustable spacer assembly and configured to transmit said actuation force.

2. A surgical instrument ofclaim 1, wherein said first jaw member comprises a compression gauge jaw member instrumented with a force gauge assembly comprising a compression head and a force transducer, and said second jaw member comprises an anvil jaw member.

3. A surgical instrument ofclaim 1, wherein said surgical instrument further comprises a signal processor and display unit.

4. A surgical instrument ofclaim 1, wherein said at least one control link is operably joined with said control mechanism at said first end and said spacer base comprising said adjustable spacer assembly at said second end.

5. A surgical instrument ofclaim 4, wherein said at least one control link is configured to transmit a linear actuation force.

6. A surgical instrument ofclaim 4, wherein said at least one control link is configured to transmit a rotational actuation force.

7. A surgical instrument ofclaim 1, wherein said at least one control link is selected from the group including a wire, a rigid rod, a fluid line, a threaded rod, a rigid bar and a bar flexible lengthwise.

8. A surgical instrument ofclaim 7, wherein said at least one control link further comprises a tubular housing.

9. A surgical instrument ofclaim 1, wherein said at least one control link is terminated at said second end with a force conversion mechanism selected from the group including a screw on a threaded shaft, a worm gear drive, a rack and pinion gears, a crank mechanism and a cam drive mechanism to convert a linear actuation force to a rotation actuation force, vice versa, which is operably joined with said spacer base.

10. A surgical instrument ofclaim 1, wherein said at least one control link comprises a cam follower disposed at said first end and said control mechanism comprises a cam drive mechanism comprising a thumbwheel comprising a cam groove configured to receive said cam follower.

11. A surgical instrument ofclaim 10, wherein said thumbwheel comprising said control mechanism produces a pull force on said at least one control link when rotated in one direction and a push force when rotated in the other direction.

12. A surgical instrument ofclaim 1, wherein said control mechanism comprises a slider-crank mechanism comprising a thumbwheel and a crank pivotally joined with a pivot disposed on said thumbwheel on one end and said at least one control link on the other end.

13. A surgical instrument ofclaim 12, wherein said thumbwheel comprising said control mechanism produces a pull force on said at least one control link when rotated in one direction and a push force when rotated in the other direction.

14. A surgical instrument ofclaim 1, wherein said control mechanism comprises a rack-and-pinion gear mechanism comprising a thumbwheel, a pinion gear and a rack gear fixedly joined with said at least one control link.

15. A surgical instrument ofclaim 14, wherein said thumbwheel comprising said control mechanism produces a pull force on said at least one control link when rotated in one direction and a push force when rotated in the other direction.

16. A surgical instrument ofclaim 1, wherein said control mechanism comprises a thumbwheel drive mechanism comprising a thumbwheel coaxially joined with said at least one control link.

17. A surgical instrument ofclaim 1, wherein said at least one control link comprises a threaded rod disposed at said first end and said control mechanism comprises a screw drive mechanism comprising a thumbwheel having a threaded hole coaxially disposed therewith configured to receive said threaded rod comprising said at least one control link.

18. A surgical instrument ofclaim 1, wherein said control mechanism comprises a worm drive mechanism comprising a worm and a worm gear whose rotation axis is fixedly joined with said at least one control link.

19. A surgical instrument comprising:

a handle;

an elongated shaft disposed distally and operably coupled to said handle;

an end effector disposed distally and operably coupled to said elongated shaft, said end effector comprising:

a first jaw member and a second jaw member pivotally joined for pivotal motion with respect to each other to capture and compress a tissue there-between, and configured to open and close when operated by said handle;

an adjustable spacer assembly comprising an adjustable spacer member and a spacer base disposed on said first jaw member;

an actuation mechanism supported by said elongated shaft and disposed adjacent to said handle for producing an actuation force for controlling said adjustable spacer assembly; and

at least one force transmission mechanism disposed in said elongated shaft operably engaged with said actuation mechanism and said spacer base comprising said adjustable spacer assembly, and configured to transmit said actuation force.

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